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Placenta previa during pregnancy. Partial placenta previa

Placenta previa is one of the serious complications of pregnancy, in which natural childbirth is impossible, and in addition, there is a high chance that complications will develop, due to which both the fetus and its mother are at risk of death. In this regard, such pregnancies are carried out with great care in order to prevent dangerous ones due to a similar, abnormally located placenta. A woman often has to stay in a hospital for a long time and be constantly under the supervision of doctors. But it is quite possible to endure and give birth to a healthy baby. It is important to know as much as possible about this pathology.

Placenta previa: what is it?

In the uterus, exclusively during pregnancy, for the purpose of nutrition and development of the fetus, a temporary organ is formed - the placenta. It grows and develops in parallel with the fetus, and after its birth, the placenta, along with the fetal membranes, is separated from the walls of the uterus. From the placenta, which has two sides - the fetus and the mother, the umbilical cord departs, it is a gelatinous, connective tissue cord, inside of which there are vessels through which blood enters the fetus, bringing it oxygen and nutrients for life and removing carbon dioxide and metabolic products.

With a physiologically developing pregnancy, the placenta is located in the region of the fundus of the uterus (the part facing upwards towards the mother's chest) or along its side walls. This is due to the fact that these parts of the uterus are thicker and richly supplied with blood, which allows the fetus to develop well and fully without suffering from a lack of nutrition and oxygen. If, during implantation, the embryo is located in the region of the lower segment, closer to the neck, and the placenta began to develop in such a way that, during its development, it completely or partially blocked the exit from the uterus, they speak of its presentation. This is a complication of pregnancy, which not only disrupts the nutrition of the fetus, since the walls of the uterus in this part are not so powerful, but also becomes an obstacle to the natural birth of the child, the exit from the uterus is blocked by the placenta, which cannot be born ahead of the child. If it begins to exfoliate and move away during childbirth, it threatens with bleeding and death of the mother and fetus.

Classification of types of presentation possible

This pathology of pregnancy has several classifications, but the most commonly used options are:

Full presentation , this is the location of the placenta, completely covering the internal os of the uterus (the opening through which the baby is born). With this arrangement, the placenta passes with its shares from one wall to the second, hanging over the uterine pharynx. At the same time, the fetal membranes are not determined during obstetric examination.
incomplete placenta previa , or partial. With it, the placenta is not completely located above the uterine os, partially overlapping it .

In this type of presentation, there are two options:

Lateral presentation , with it, one or two lobes of the placenta pass to the uterine pharynx, the fetal membranes are determined with their typical roughness.
marginal presentation , in which the site of the placenta is located in the area of \u200b\u200bthe internal uterine os, but does not leave its limits (that is, the opening is only partially closed).

Low placentation: features

A special option, close to placenta previa, but not so critical, is considered low placentation. With it, there is not even a partial covering of the uterine os from the inside, but the placenta is located critically low to the pharyngeal area, less than 5 cm from the area of the internal pharynx during the third trimester of gestation and less than 70 mm from the area of \u200b\u200bthe internal pharynx for periods up to 26 weeks of pregnancy.

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With regard to low placentation during pregnancy, doctors are more favorable in prognosis, especially if it is detected early. With it, bleeding that threatens the life of the fetus and mother rarely occurs, and the placenta, against the background of the progression of pregnancy, tends to migrate, move upward due to the growth of the uterus and stretching of its fibers.

Due to this, as the terms increase, it is also possible to expand the gap between the uterine os and the edge of the placenta. Usually it rises, due to which the state of low placentation is eliminated by the end of pregnancy, and, accordingly, all complications that are associated with the presentation and marginal location of the placenta disappear in this condition. With a low placentation, childbirth is quite possible in a natural way.

Why is the placenta positioned incorrectly?

Usually, for such a complication, there must be certain prerequisites, and it is noted that such a pathology is most typical for repeated pregnancies and childbirth. In primiparas, this complication is rare.

The main factors that can affect the atypical location of the placenta may be changes in the endometrium due to various organic causes (structural problems).

These include inflammatory processes in the uterus as a result of infections, repeated surgical interventions and abortions, operations. Those who left rough scars on the uterus, interventions for the removal of fibroids, as well as after multiple and complicated births. In addition to those listed, the following may also be relevant:

Unremoved uterus of a significant size in the area of the bottom and walls
, a pathology in which the endometrium is formed in atypical places for it
Infantilism with underdevelopment of the uterus or malformations in its development (saddle, with partitions, bicornuate)
Inflammatory processes in the cervical region, anatomical defects from previous births
The presence of isthmic-cervical insufficiency (the cervix is weak and cannot hold the fetus).

The influence of the embryo itself in the period of implantation was also revealed, with the release of special substances by it.. So, when penetrating into the uterus from the fallopian tube, the embryo is implanted in a place where the richest circulatory network and optimal conditions for development. During implantation, they secrete special proteolytic enzymes that dissolve the endometrium and immerse it in the thickness. If this process is slowed down, then the embryo cannot attach itself in the region of the uterine fundus, sliding closer to the cervix, and only there it manages to gain a foothold, further forming a placenta around itself, which will block the exit from the uterus as it grows.

The main symptoms of presentation

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Actually, before the onset of complications, such a pathology of pregnancy does not manifest itself in any way. It does not give pain, discomfort or problems in the growth of the abdomen.

Its most frequent and typical manifestation, which is also a complication of pregnancy, is recurrent. Bleeding or spotting may occur, daubing can occur at different times, starting from the earliest. This is largely determined by the localization of the fetal egg and the degree of presentation. Most often, repeated bleeding is formed from the second half, when the placenta and uterus are actively growing, and the fetus is already pressing on the walls and area of the placenta. In the last weeks, as training bouts become more frequent, there is usually an increase in the intensity of bleeding.

The main reason for the appearance of blood on linen during presentation is the detachment of individual sections of the placenta above the uterine os, since the endometrium is capable of active and strong contractions, but the placenta is not. The placenta also does not have time to stretch after the walls of the uterus as the gestation progresses, and in the zone of greatest stretching and tension, it exfoliates from the wall of the uterus, exposing the vessels that bleed.

Considering the fact that it is the lower segments of the uterus that are most extensible by the end of pregnancy, it is also clear why the placenta should normally be at the bottom or on the sides of the uterus - there is less contractility and extensibility of tissues.

Previa may not manifest itself in any way before childbirth, but with the onset of active repeated uterine contractions, the placenta begins to exfoliate, forming life-threatening bleeding and the formation of hematomas between it and the uterine wall, which threatens fetal asphyxia. At the same time, the woman does not feel any pain, the placenta does not have pain receptors, as well as the endometrium, their detachment is invisible to the woman, only blood on the linen and progressive malaise due to blood loss are visible.

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Not only the mother loses blood, but also the fetus, moreover, it receives little oxygen through the remaining zones of the attached placenta, which leads to acute asphyxia if more than half of the area exfoliates.

Features of bleeding: provocateurs and symptoms

As provoking factors for uterine contractions with such an anomaly in the location of the placenta, various factors can act - physical activity, intimacy, sharp coughing shocks against the background of a cold, examination by a doctor in an armchair with an increase in intra-abdominal pressure when straining, taking a hot bath or going to the sauna.

There are some differences in the development of bleeding against the background of full and partial presentation, which should be remembered by the doctor and the pregnant woman herself:

If this is a full presentation:

Bleeding usually occurs against the background of complete health, even without the influence of provoking factors and any subjectively unpleasant, especially pain, sensations. At the same time, it is plentiful and can lead to a large blood loss and a threat to life in a short period. It can also spontaneously stop itself, but after a certain period of time it resumes again. Or it may in the future take the form of discharges of a bloody nature and a meager volume, but appearing regularly. In the last weeks of gestation, bleeding may resume or increase sharply in intensity.

If it is an incomplete presentation:

Bleeding usually occurs at the end of the gestation period, or begins just before the onset of labor, as false contractions intensify or turn into true ones. The strength of the bleeding depends on the volume of the exfoliated placenta, the larger the amount of tissue exfoliated from the uterine wall, the more abundant the blood loss. There is no pain or discomfort in the genital tract and lower abdomen.

At the same time, recurrent bleeding, which is typical for presentation, in most cases leads to the development of a post-hemorrhagic form of anemia (due to blood loss), in blood tests they show a decrease in hemoglobin and hematocrit in parallel with a decrease in red blood cell volume.

What complicates placenta previa

Against the background of the existing presentation, pregnancy is often also complicated by other pathologies. These include the threat of interruption, which is caused by the same factors as the presentation itself. Often, against the background of presentation, especially if it is complete, they are formed, with the birth of a child of varying degrees of prematurity.

In expectant mothers with presentation, hypotension of pregnant women is often detected, it is typical for 35% of cases, which is associated with anemia of the body and changes in vascular tone. In order to avoid all possible complications and bleeding, when managing pregnant women in the hospital, they are prescribed drugs to reduce uterine tone and reduce excitability and muscle contractility.

Preeclampsia is also typical for such pregnant women - this is a complication of the second half of pregnancy, in which pressure rises, develops and manifests itself. It leads to severe violations of the uteroplacental circulation, which leads to hypertension and edema, as well as disruption of the kidneys, due to which protein is massively lost. Presentation and mutually aggravate and aggravate the course of pregnancy.

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Due to the disruption of the functioning of organs and systems during preeclampsia, the coagulation function of the blood is sharply disrupted, which leads to recurrent bleeding, which stops much worse due to the fact that thrombosis does not occur in small vessels.

Placenta previa also threatens placental insufficiency in terms of delivering oxygen and nutrients to the fetus, which leads to a lag in its mass and growth, and leads to the formation of IUGR ( child underdevelopment syndrome in the womb). That part of the placenta that exfoliates during bleeding is disabled from functioning, and cannot actively participate in gas exchange and nutrition of the fetus. Back after detachment, this part of the placenta no longer grows, a hematoma is usually formed, which prevents the restoration of the integrity of the placental site.

In the presence of placenta previa, the position of the fetus also suffers, often it becomes transverse or oblique, which is unfavorable for its development and leads to the fact that during its movements the uterus is even more stretched, which creates the prerequisites for placental abruption and bleeding. For childbirth, this will not be an obstacle, given the fact that they cannot be natural, and during a cesarean section, the position of the fetus will be taken into account by doctors.

How is this anomaly diagnosed?

Actually, the diagnosis of placental presentation in modern obstetrics has no difficulties. First, the future mother's complaints about recurring bleeding or spotting will be typical. Usually, bloody discharges that repeat from the middle of the gestation period create an assumption of complete presentation, that is, the exit is closed by the abnormally located placenta on the entire circumference of the uterine pharynx. If bleeding occurs in the final weeks of pregnancy or already at the initial stage of childbirth, this is a partial presentation, the abnormally lying placenta only partially blocks the exit.

If bleeding is detected, the doctor should carefully examine the woman on the chair, evaluating the walls of the vagina with the condition of the cervix using mirrors to exclude traumatic or other causes of bleeding. Also, with such a vaginal examination of expectant mothers, the signs of an abnormally located placenta are quite clearly defined. But such techniques can increase bleeding or can provoke other complications.

Therefore, today it becomes the leading one, while becoming the most informative in making such a diagnosis. It evaluates the location, together with the overall size of the placenta, its structure and the detection of bloody accumulations between it and the uterine walls. Due to ultrasound scanning, it turns out whether the presentation is complete, or only part of the placental site covers the pharynx (which of the incomplete ones). When examining the placenta, when a state of presentation is suspected, it becomes important to determine the area of the placenta with the exact size of the defect (detachable area), the degree of blood flow disturbance in the vessels of the fetus and umbilical cord. Also in the dynamics it is possible to evaluate the migration of the placenta up to 34 weeks, when it can still change its position due to the growth of the lower uterine segment.

Features of ultrasound diagnosis of placenta previa

When during the study, based on the data, the presentation is determined (moreover, it is complete), it is strictly forbidden to use vaginal examinations so as not to provoke bleeding. When there is only partial presentation, its criteria are the length of the gap from the edge of the placenta to the opening that makes up the internal pharynx. If it is 50 mm or smaller, it is a low-lying placenta. When placental tissue is found in the area of \u200b\u200bthe internal pharynx, this is presentation. From the period of the second and then the third trimesters of gestation, until the period of the 28th week, the position of the placenta is judged by measuring the gap from the inner edges of the uterine os to the placental tissue, this size is compared with the diameter of the baby's head.

If an abnormal position of the placenta is detected, it is dynamically controlled according to ultrasound data for periods up to 34 weeks of pregnancy, when the placenta takes its final position. So, for evaluation in dynamics, at least three studies are carried out at the time of the 16th week, then at 25 weeks and 35 weeks.

Ultrasound is recommended when the bladder is not empty, so the position of the uterus and placenta will be better seen. Additionally, it is possible to determine a hematoma under the placental site and the wall of the uterus due to ultrasound scanning (if it has already been established that there is a presentation). With such a hematoma, bleeding does not always develop and not in all mothers, and there is no outflow of blood from the uterine cavity. If the detachment is no more than 25% of the area, the life of the fetus may not be in danger, but if it increases to one third or more, the fetus may die from

How is pregnancy with a similar problem

In each situation, the tactics of pregnancy management will be individually selected by an obstetrician-gynecologist, based on how often bleeding occurs and how pronounced, how much blood is lost by the woman and what are the complications and degree of anemia. If bleeding does not appear at the beginning of gestation (until the middle of the term), a woman can be at home, being observed by a doctor at a polyclinic in compliance with a special daily regimen and with the elimination of any provocateur factors. Any loads, stresses are limited and a strict ban on intimacy is imposed. Upon reaching the gestational age of 24 weeks or more, inpatient observation is necessary, even if the state of health is excellent and there are no bleeding or any complaints. Supportive therapy and treatment of all concomitant disorders is carried out in order to bring the pregnancy to the due date of 37-38 weeks. This is permissible with rare and mild bleeding, with a normal general condition of the woman herself against the background of a completely normal development of the fetus.

Even if the bleeding was once, and then everything is fine with the pregnancy, after a period of 24 weeks, she is not discharged from the hospital until the baby is born.

If the condition creates concern, then in a clinic for pregnant women a special regimen is indicated:

Bed rest almost always
prescribing medications that relieve excitability and contractile activity of the myometrium
Treatment of anemia by prescribing iron-containing medicines, with severe, not eliminated blood loss - the use of blood-substituting solutions and wildness,
Correction of uteroplacental insufficiency.

When the pregnancy is delivered to the term of 37 weeks or more in the hospital, but the state of placenta previa is preserved, based on the current situation, delivery is planned and preparations for the operation begin.

How is childbirth carried out: operation or not?

An unconditional indication for, carried out as a planned operation, is complete placenta previa. No matter how much a woman would like, childbirth in a natural way is physically impossible, because the placenta blocks the exit from the uterus, exfoliates before the birth of the fetus and leads to its acute asphyxia and death in the womb. In addition, the placenta will not allow the presenting part of the fetus - the head or buttocks - to be inserted into the small pelvis. As the uterus contracts, detachment of the placenta occurs at a progressive pace, from which the mother can also die from blood loss during childbirth.

Against the background of incomplete presentation and in the presence of complications in the form of breech presentation, malposition of the fetus in the uterus, scars after surgical delivery earlier or when, with a woman's age after 30 years and a narrow pelvis, presence, a caesarean section is also performed as a planned operation. If there are no complications with incomplete presentation, there is no bleeding and even discharge, the doctor waits for the moment when active labor begins, performing an amniotomy (opens the fetal bladder). If after this bleeding opens (which means placental abruption), an emergency caesarean section is performed.

If bleeding opens with incomplete presentation before the onset of active labor, a rupture of the fetal bladder is performed. With such a procedure, the descending head of the fetus in the pelvic area can press the edge of the placenta along the zone of its exfoliation, and stops bleeding. In a situation where bleeding does not decrease or there are no signs of cervical maturity, doctors make a decision - it is carried out emergency caesarean section . If the cervix is mature and there is no more bleeding, preference is given to the delivery of the baby through the natural birth canal.

What complications can be in pregnant women or women in childbirth?

Such a complication of pregnancy is dangerous both during gestation and at the beginning of childbirth and after their completion. So, during pregnancy, the threat of interruption and fetal hypoxia, IUGR syndrome and the death of the child, bleeding are possible. In addition, often with placenta previa, its dense attachment and accretion of the placenta are also possible, which threatens with complications in the third stage of labor, when detachment of the placenta from the uterine walls is necessary. If it does not separate, it is necessary, in order to save the life of the mother, to go for an operation to extirpate the uterus (remove it with ligation of the vessels).

The most common complication is bleeding, which begins both during pregnancy and with the onset of active labor, as contractions become more frequent. In this case, doctors resort to partial presentation of the membranes as an attempt to eliminate detachment. In order to reduce the risks for such pathologies, doctors in 80% of cases choose for delivery.

Is it possible to give birth with placenta previa

You can naturally give birth with low placentation and partial presentation, if the baby is head down and labor is active, the cervix is ripe, and there is no bleeding after opening the bladder. In addition to bleeding, complications in such childbirth can be the weakness of the birth forces and the fetal hypoxia that develops against this background.

When conducting childbirth in a natural way, constant CTG monitoring of the fetus and how the uterus contracts is necessary. A woman spends the first stage of labor with sensors on her stomach that record uterine activity and contractions, and against the background of them, a change in the heartbeat of the fetus. Signs of complications according to monitoring data are a reason for an immediate emergency caesarean section.

After natural childbirth, bleeding may resume due to a violation of the process of separation of the placenta, since it is located in the area of the lower sections of the uterus, which contract worse. It may be necessary to put the woman under anesthesia and manually separate the placenta. There may be a large blood loss due to the reduced tone of the uterus and damage to the choroid plexuses in the area of its neck with an atypical location of the placenta, which exfoliated over a large area.

Alena Paretskaya, pediatrician, medical commentator

If you have (or placenta previa), then this means that your placenta is located abnormally low in the uterus, near the exit to the cervix (internal os) or overlaps it. The placenta is a disc-like organ that is usually located at the top of the uterus and provides nutrients to the baby through the umbilical cord.

If presentation is detected early in pregnancy, it is usually not considered a problem. But if the placenta remains too close to the cervix and at later dates, then this can cause serious bleeding, which leads to other complications of pregnancy and often becomes. If the presentation persists until the end of pregnancy, then the birth is carried out by caesarean section.

If the placenta covers the entire cervix, it is called full presentation . If it is in close proximity to the cervix, it is called incomplete presentation . You may also hear the term " partial presentation ”, which characterizes the condition when the placenta covers only part of the neck of the internal pharynx. If the edge of the placenta is within two centimeters of the internal os, but does not border it, this is called low implantation of the placenta (or low placentation).

The location of the placenta is usually checked between 16 and 20 weeks, during the second routine fetal ultrasound, and if necessary later, during the next ultrasound.

Risk factors for the development of placental presentation

Most women who develop do not have obvious risk factors. But if the expectant mother has one of the following factors, then she is likely to develop this complication:

placenta previa during a previous pregnancy;
the presence of a caesarean section in the past (the more caesarean sections, the higher the risk);
the presence of operations on the uterus (such as cleaning the uterus or);
multiple pregnancy;
, drug use;
the onset of pregnancy in adulthood, this is especially true;
if a woman already has several children (the more children, the higher the risk).

Management of pregnancy with placental presentation

The management of such a pregnancy primarily depends on its duration. Don't panic if your mid-pregnancy ultrasound shows you have placenta previa. As your pregnancy progresses, the placenta may "migrate" further away from the cervix and presentation will no longer be a problem. During your third trimester ultrasound, your doctor will recheck the location of your placenta.

Only a small percentage of women who are diagnosed with low placentation, this condition persists until childbirth. Usually during the third ultrasound, the placenta is in a normal position. But there is one “but”: if the placenta previa is complete, then it will most likely remain so. The tendency of the placenta to "migration" is noted only with incomplete (partial) presentation and low placentation. In general, during childbirth occurs in one case out of 200 births.

If an ultrasound in the third trimester shows that the placenta is still overlapping or too close to the internal os, the woman is not recommended to have internal gynecological examinations and cervical smears. In addition, she needs to calm down and avoid all kinds of activities that can provoke bleeding from the vagina, such as housework, heavy physical labor (including carrying heavy bags of groceries!), and she is also contraindicated for exercise.

When it's time to give birth, the woman will have a caesarean section. In complete presentation, the placenta blocks the baby from leaving the uterus. And even if the placenta only partially overlaps or borders the exit from the uterus, the woman still needs to have a caesarean section, because in most cases the placenta begins to bleed as the cervix dilates.

It is likely that in the background placental presentation a woman in the third trimester may have painless vaginal bleeding. In such cases, especially if spasmodic contractions of the uterus join the bleeding, the woman should be hospitalized. Bleeding occurs when the cervix begins to open slightly, and during its expansion, trauma to the blood vessels in the cervix occurs. If the baby is almost full-term, then the woman will immediately undergo a caesarean section.

If the child is still very early to be born, then a cesarean will be performed only if the child's condition requires immediate delivery, or if the woman has heavy bleeding that cannot be stopped. If the condition is stable, then the expectant mother will be observed in the hospital until the bleeding stops. If the pregnancy is less than 34 weeks, she may be given corticosteroids to speed up the development of the baby's lungs in case the baby is born prematurely.

If the bleeding has stopped and does not resume for at least a couple of days, and if both the expectant mother and her baby are in good condition, then the woman can be discharged home. In such cases, a woman is usually scheduled for a planned caesarean section for a period of about 37 weeks, unless there is no reason for an earlier delivery.

Complications from placental presentation

Having placenta previa makes it more likely for a woman to bleed heavily and need a blood transfusion. This applies not only to pregnancy, but also to the birth process and the postpartum period. And that's why:

After the baby is removed from the uterus (by caesarean section), the obstetrician-gynecologist removes the placenta and the woman is given "Oxytocin" (and other drugs if necessary). Oxytocin causes uterine contractions, which help stop bleeding from the area where the placenta was implanted. But if a woman has placenta previa, then the placenta is implanted in the lower, and not in the upper, part of the uterus, and uterine contractions in this case are not as effective in stopping bleeding.

In women with placental presentation very often it turns out that the placenta is implanted too deeply, and it is extremely difficult to separate it during childbirth. This is called placenta accreta. The augmentation can cause massive bleeding and necessitate multiple blood transfusions during childbirth. This can be life threatening and a hysterectomy (removal of the uterus) may be needed to stop the bleeding. Finally, if a woman is forced to go into labor much too early, her baby will be at risk of complications from preterm labor, such as breathing problems and very low birth weight.

Placenta previa during pregnancy is considered one of the serious complications during childbearing and subsequent childbirth. The fact is that the situation when the placenta completely or partially covers the uterine os, and this is placenta previa, is irreparable - there is no way to correct this state of affairs with medication, although there is always a chance that it will move out of the lower uterus on its own.

The only symptoms that may indicate placenta previa during pregnancy are painless bleeding. They occur, as a rule, closer to the second half of pregnancy against the background of complete well-being.

Causes of placenta previa

Placenta previa is diagnosed by ultrasound, and the final diagnosis can be made after 24 weeks - before that there is a chance that the placenta will change position on its own. In addition to the fact that ultrasound determines the final diagnosis of "placenta previa", this method also makes it possible to determine the options for presentation, the size and area of the placenta, the degree of detachment.

The reasons for the occurrence of placenta previa during pregnancy can be changes in the mucosa of the inner wall of the uterus as a result of repeated abortions, inflammations or genital infections, previously complicated childbirth.

The disposition to such a pathology is more inherent in women with deformities of the uterine cavity, caused by congenital anomalies or acquired (for example, as a result of uterine fibroids).

The cause of placenta previa can even be diseases of the heart, liver or kidneys, accompanied by congestion in the pelvic organs (including the uterus).

In addition, placenta previa is three times more common in women who give birth for the first time.

Depending on the location of the placenta, there are low presentation (attachment) of the placenta, complete (central) or partial presentation (may be lateral or marginal).

Low placenta previa

In the normal course of pregnancy, the placenta is located along the bottom or body of the uterus, along the anterior (less often posterior) wall with the transition to the lateral walls. Low placenta previa is characterized by a situation where the placenta is located in close proximity to the internal os of the cervix - at a distance of 6 cm or even less.

Such a pathology is most often determined in the second trimester of pregnancy during the next ultrasound. But at the same time, if low placenta previa was still diagnosed in this period, there is a possibility that over time, as the pregnancy develops, the placenta will take a “normal position”.

Conventionally, this state of affairs is called "migration", and the movement of the placenta is caused by stretching and stretching of the tissues of the uterus. So, as the fetus develops, the elastic tissues of the lower part of the uterus gradually rise upwards. At the same time, there is also some upward movement of the placenta, due to which its location becomes normal. Therefore, if the low location of the placenta was found in the second trimester of pregnancy, there is a fairly high probability of its movement by the end of pregnancy and the normalization of the situation.

Marginal placenta previa

Partial, or incomplete placenta previa, is its location, in which the internal os of the uterus is blocked by the placenta, but not completely. One type of partial placenta previa is marginal placenta previa.

With the marginal location of the placenta, its lower edge is at the level of the edge of the internal os, while the outlet of the uterus is closed by the tissue of the placenta by about a third.

Usually, marginal placenta previa is diagnosed in the second trimester of pregnancy with the help of ultrasound, against the background of complaints of a pregnant woman about constant bleeding. If marginal placenta previa has been determined, the woman needs careful medical supervision and all necessary studies. As needed, iron-containing preparations can be prescribed - in order to avoid bleeding and the development of anemia due to a decrease in hemoglobin levels.

Complete placenta previa (central placenta previa)

Complete placenta previa is probably the most serious pathology associated with the incorrect location of the placenta. Full presentation is said when the placenta completely closes the internal pharynx, during the vaginal examination, placental tissue is determined everywhere, the fetal membranes are not palpable. If, in addition, it is possible to establish that the center of the placenta is located at the level of the pharynx, a diagnosis of central placenta previa is made.

Partial placenta previa is diagnosed with a frequency of 70-80% of the total number of presentations. At the same time, full presentation accounts for 20-30% of cases, and this, unfortunately, is not a small indicator at all.

With complete placenta previa, a woman, even in the absence of bleeding, must be sent to a hospital. Diagnosed central presentation is a serious pathology in which a pregnant woman must be provided with constant qualified medical supervision.

Treatment of placenta previa

If a presentation was detected, the doctor will determine the treatment regimen and follow-up actions based on the specifics of placenta previa. But be that as it may, in the case when a pregnant woman was diagnosed with placenta previa, she will need constant monitoring by specialists.

If bleeding is not observed, the expectant mother may be allowed to be observed on an outpatient basis. At the same time, she needs to avoid stress - both physical and emotional, exclude sexual contact, sleep at least 8 hours a day and walk as much as possible. You will also need a special diet that involves the consumption of foods rich in iron, protein and vitamins. A diet is necessary to maximize the intake of useful substances into the body of a pregnant woman: with placenta previa, part of it does not participate in gas exchange, which can provoke. In the meantime, mommy may experience anemia or, which also become a consequence of placenta previa during pregnancy.

If, after 24 weeks, the pregnant woman has periodic bleeding, she will be offered to go to the hospital, where she can always be provided with emergency care in case of possible complications. In this case, doctors are recommended to be observed permanently until the end of pregnancy. If the bleeding is minor, and the woman's health has not worsened, they resort to conservative methods of treatment: the pregnant woman is prescribed bed rest, complete rest, drugs that lower the tone of the uterus and improve blood circulation. If found in a future mother, she is prescribed drugs to increase hemoglobin levels, as well as means for general strengthening of the body.

Childbirth with placenta previa

Placenta previa during pregnancy is an indication for delivery by caesarean section, in the case of complete presentation, it is mandatory, since other ways of delivery are not possible. If the pregnancy was saved, then a caesarean section is carried out for a period of 38-39 weeks.

With incomplete placenta previa, childbirth is also possible, but they are associated with a certain risk. In addition, for natural childbirth with incomplete placenta previa, obligatory cessation of bleeding after opening of the fetal bladder, a mature cervix, good labor activity and head presentation of the fetus become mandatory conditions. In other cases, if the birth proceeds naturally, there is a high risk of complete detachment of the placenta, which will lead to very heavy bleeding. And this is fraught with serious complications - even death for both the mother and the baby.

Specially for- Tatyana Argamakova

Location of the placenta: norm and pathology, causes of anomalies, symptoms and possible complications, diagnosis and treatment. Childbirth and precautions

The placenta is an organ located in the uterus and functions only during pregnancy. It is thanks to him that the normal development of pregnancy until the very birth becomes possible, therefore it is important that the placenta "works" normally. In this case, not only the correct structure of the placenta is important, but also its correct location. Placenta previa is a serious complication of pregnancy, which, fortunately, is not very common.

The placenta is laid at the very beginning of pregnancy and is fully formed. It provides nutrition to the fetus, excretion of metabolic products, and also performs the function of the lungs for it, because. it is through the placenta that the fetus receives the oxygen necessary for its life. In addition, the placenta is a real "hormonal factory": hormones are formed here that ensure the preservation, normal development of pregnancy, growth and development of the fetus.

The placenta is made up of villi - structures within which blood vessels pass. As pregnancy progresses, the number of villi, and, accordingly, the number of blood vessels is constantly growing.

Location of the placenta: norm and pathology

From the side of the uterus at the site of attachment of the placenta there is a thickening of the inner membrane. Deepenings are formed in it, which form the intervillous space. Some placental villi fuse with maternal tissues (they are called anchor), while the rest are immersed in maternal blood, which fills the intervillous space. Anchor villi of the placenta are attached to the partitions of the intervillous spaces, vessels pass through the thickness of the partitions, which carry maternal arterial blood saturated with oxygen and nutrients.

The villi of the placenta secrete special substances - enzymes that "melt" the small arterial vessels that carry maternal blood, as a result of which blood flows out of them into the intervillous space. It is here that the exchange between the blood of the fetus and the mother takes place: with the help of complex mechanisms, oxygen and nutrients enter the blood of the fetus, and metabolic products of the fetus enter the mother's blood. The fetus is connected to the placenta by the umbilical cord. One end is attached to the umbilical region of the fetus, the other to the placenta. Inside the umbilical cord are two arteries and a vein that carry blood, respectively, from the fetus to the placenta and vice versa. Blood rich in oxygen and nutrients flows through the vein of the umbilical cord to the fetus, and venous blood from the fetus, containing carbon dioxide and metabolic products, flows through the arteries.

Normally, the placenta is located closer to the bottom of the uterus along the anterior or, less often, its posterior wall. This is due to more favorable conditions for the development of the fetal egg in this area. The mechanism for choosing the place of attachment of the fetal egg is not completely clear: there is an opinion that the force of gravity plays a role in choosing a place - for example, if a woman sleeps on her right side, then the egg is attached to the right wall of the uterus. But this is just one of the theories. We can only say unequivocally that the fetal egg does not attach to places that are unfavorable for this, for example, to the locations of myomatous nodes or to places of damage to the inner lining of the uterus as a result of previous curettage. Therefore, there are other options for the location of the placenta, in which the placenta is formed closer to the lower part of the uterus. Allocate a low location of the placenta and placenta previa.

They say about the low location of the placenta when its lower edge is at a distance of no more than 6 cm from the internal pharynx of the cervix. This diagnosis is established, as a rule, during ultrasound. Moreover, in the second trimester of pregnancy, the frequency of this pathology is about 10 times higher than in the third trimester. It's pretty easy to explain. Conventionally, this phenomenon is called the "migration" of the placenta. In fact, the following happens: the tissues of the lower part of the uterus, very elastic, with an increase in the duration of pregnancy, undergo significant stretching and stretch upwards. As a result of this, the lower edge of the placenta seems to move upward, and as a result, the location of the placenta becomes normal.

Placenta previa is a more serious diagnosis. In Latin, this condition is called placenta praevia. "Pre via" literally means before life. In other words, the term "placenta previa" means that the placenta is on the way to the emergence of a new life.

Placenta previa is complete or central, when the entire placenta is located in the lower part of the uterus and completely covers the internal cervical os. In addition, there is a partial placenta previa. It includes marginal and lateral presentation. They say about lateral presentation of the placenta when up to 2/3 of the outlet of the uterus is covered with placental tissue. With marginal placenta previa, no more than 1/3 of the opening is closed.

Causes of anomalies

The main cause of anomalies of placental attachment are changes in the inner wall of the uterus, as a result of which the process of attaching a fertilized egg is disrupted.

These changes are most often caused by an inflammatory process of the uterus that occurs against the background of curettage of the uterine cavity, abortion, or associated with sexually transmitted infections. In addition, deformation of the uterine cavity predisposes to the development of such a pathology of the placenta, due either to congenital anomalies in the development of this organ, or to acquired causes - uterine fibroids (benign tumor of the uterus).

Placenta previa can also occur in women suffering from serious diseases of the heart, liver and kidneys, as a result of congestion in the pelvic organs, including in the uterus. That is, as a result of these diseases, areas with worse blood supply conditions than other areas appear in the wall of the uterus.

Placenta previa in multiparous women occurs almost three times more often than in women carrying their first child. This can be explained by the "baggage of diseases", including gynecological ones, which a woman acquires by the age of the second birth.

There is an opinion that this pathology of the location of the placenta may be associated with a violation of some functions of the fetal egg itself, as a result of which it cannot attach itself to the most favorable part of the uterus for development and begins to develop in its lower segment.

Beware of bleeding!
Bleeding with placenta previa has its own characteristics. It is always external, i.e. blood flows out through the cervical canal, and does not accumulate between the wall of the uterus and the placenta in the form of a hematoma.
Such bleeding always begins suddenly, as a rule, without any apparent external cause, and is not accompanied by any pain. This distinguishes them from bleeding associated with premature termination of pregnancy, when, along with spotting, there are always cramping pains.
Often bleeding begins at rest, at night (woke up "in a pool of blood"). Once having arisen, bleeding always repeats, with greater or lesser frequency. Moreover, it is never possible to foresee in advance what the next bleeding will be in terms of strength and duration.
After such bleeding can be provoked by physical activity, sexual intercourse, any increase in intra-abdominal pressure (even coughing, straining, and sometimes a gynecologist's examination). In this regard, examination on the chair of a woman with placenta previa should be carried out with all precautions in a hospital, where emergency assistance can be provided in case of bleeding. The bleeding itself is dangerous for the life of mother and baby.

Quite often, placenta previa can be combined with its dense attachment, as a result of which the independent separation of the placenta after childbirth is difficult.

It should be noted that the diagnosis of placenta previa, with the exception of its central variant, will be quite correct only closer to childbirth, because. the position of the placenta may change. This is all due to the same phenomenon of "migration" of the placenta, due to which, when the lower segment of the uterus is stretched at the end of pregnancy and during childbirth, the placenta can move away from the area of \u200b\u200bthe internal os and not interfere with normal childbirth.

Symptoms and possible complications

The main complications and the only manifestations of placenta previa are spotting. Depending on the type of presentation, bleeding may occur for the first time during various periods of pregnancy or in childbirth. So, with central (complete) placenta previa, bleeding often begins early - in the second trimester of pregnancy; with lateral and marginal options - in the third trimester or directly in childbirth. The amount of bleeding also depends on the type of presentation. With a complete presentation, bleeding is usually more abundant than with an incomplete version.

Most often, bleeding occurs during pregnancy, when the preparatory activity of the lower segment of the uterus is most pronounced. But every fifth pregnant woman with a diagnosis of placenta previa notes the appearance of bleeding in the early stages (16-28 weeks of pregnancy).

What causes bleeding in placenta previa? During pregnancy, the size of the uterus constantly increases. Before pregnancy, they are comparable to the size of a matchbox, and by the end of pregnancy, the weight of the uterus reaches 1000 g, and its dimensions correspond to the size of the fetus along with the placenta, amniotic fluid and membranes. Such an increase is achieved, mainly due to an increase in the volume of each fiber that forms the wall of the uterus. But the maximum change in size occurs in the lower segment of the uterus, which stretches the more, the closer the term of delivery. Therefore, if the placenta is located in this area, then the process of "migration" is very fast, the low-elastic tissue of the placenta does not have time to adapt to the rapidly changing size of the underlying uterine wall, and placental abruption occurs over a greater or lesser extent. In the place of detachment, damage to the vessels occurs and, accordingly, bleeding.

With placenta previa, the threat of abortion is often noted: increased uterine tone, pain in the lower abdomen and in the lumbar region. Often, with this location of the placenta, pregnant women suffer from hypotension - stably reduced pressure. A decrease in pressure, in turn, reduces performance, causes weakness, feelings of weakness, increases the likelihood of fainting, the appearance of a headache.

In the presence of bleeding, anemia is often detected - a decrease in the level of hemoglobin in the blood. Anemia can exacerbate the symptoms of hypotension, in addition, oxygen deficiency caused by a decrease in hemoglobin levels adversely affects the development of the fetus. There may be growth retardation, fetal growth retardation syndrome (FGR). In addition, it has been proven that children born to mothers who suffered from anemia during pregnancy always have a reduced hemoglobin level in the first year of life. And this, in turn, reduces the defenses of the baby's body and leads to frequent infectious diseases.

Due to the fact that the placenta is located in the lower segment of the uterus, the fetus often takes the wrong position - transverse or oblique. Often there is also a breech presentation of the fetus, when its buttocks or legs are turned towards the exit from the uterus, and not the head, as usual. All this makes it difficult or even impossible to have a child naturally, without surgery.

Diagnosis of placenta previa

Diagnosis of this pathology is most often not difficult. It is usually established in the second trimester of pregnancy based on complaints of intermittent bleeding without pain.

The doctor on examination or during an ultrasound scan may reveal an incorrect position of the fetus in the uterus. In addition, due to the low location of the placenta, the underlying part of the child cannot descend into the lower part of the uterus, therefore, a high standing of the presenting part of the child above the entrance to the small pelvis is also a characteristic feature. Of course, modern doctors are in a much more advantageous position compared to their counterparts 20-30 years ago. At that time, obstetrician-gynecologists had to navigate only by these signs. After the introduction of ultrasound diagnostics into wide practice, the task has become much simpler. This method is objective and safe; Ultrasound allows you to get an idea of the location and movement of the placenta with a high degree of accuracy. For these purposes, it is advisable to triple ultrasound control at 16, 24-26 and at. If, according to the ultrasound examination, no pathology of the location of the placenta is detected, the doctor may, during examination, identify other causes of spotting. They can be various pathological processes in the vagina and cervix.

Observation and treatment of placenta previa

An expectant mother who has been diagnosed with placenta previa needs careful medical supervision. Of particular importance is the timely conduct of clinical trials. If even a slightly reduced level of hemoglobin or disorders in the blood coagulation system are detected, the woman is prescribed iron supplements, because. in this case, there is always a risk of rapid development of anemia and bleeding. If any, even minor, deviations in the state of health are detected, consultations of the relevant specialists are necessary.

Placenta previa is a formidable pathology, one of the main causes of serious obstetric bleeding. Therefore, in the event of bleeding, all a woman’s health problems, even small ones, can aggravate her condition and lead to adverse consequences.

regime plus diet
If there is no bleeding, especially with a partial variant of placenta previa, a woman can be observed on an outpatient basis.
In this case, it is recommended to observe a sparing regime: physical and emotional stress should be avoided, sexual contacts should be excluded. It is necessary to sleep at least 8 hours a day, more to be in the fresh air.
In the diet, there must be foods rich in iron: buckwheat, beef, apples, etc. Be sure to have a sufficient protein content, because. without it, even with a large intake of iron, hemoglobin will remain low: in the absence of protein, iron is poorly absorbed. It is useful to regularly eat vegetables and fruits rich in fiber, because. stool retention can provoke the appearance of spotting. Laxatives for placenta previa are contraindicated. Like all pregnant women, patients with placenta previa are prescribed special multivitamin preparations. If all these conditions are met, the manifestations of all the symptoms described above, which in most cases accompany placenta previa, are reduced, which means that conditions are provided for the normal growth and development of the child. In addition, in the event of bleeding, the adaptive capabilities of the woman's body increase, and blood loss is more easily tolerated.

In the presence of spotting, observation and treatment of pregnant women with placenta previa at gestational ages over is carried out only in obstetric hospitals that have conditions for providing emergency care in an intensive care unit. Even if the bleeding has stopped, the pregnant woman remains under the supervision of the hospital doctors until the due date.

In this case, treatment is carried out depending on the strength and duration of bleeding, the duration of pregnancy, the general condition of the woman and the fetus. If the bleeding is insignificant, the pregnancy is premature and the woman feels well, conservative treatment is performed. Strict bed rest, drugs to reduce the tone of the uterus, improve blood circulation are prescribed. In the presence of anemia, a woman takes drugs that increase the level of hemoglobin, general strengthening drugs. Calming agents are used to reduce emotional stress.

childbirth

With complete placenta previa, even in the absence of bleeding, a caesarean section is performed at 38 weeks of gestation, because. spontaneous childbirth in this case is impossible. The placenta is located on the way the baby leaves the uterus, and if you try to give birth on your own, it will completely detach with the development of very severe bleeding, which threatens the death of both the fetus and the mother.

The operation is also resorted to at any stage of pregnancy in the presence of the following conditions:

placenta previa, accompanied by significant bleeding, life-threatening;
recurrent bleeding with anemia and severe hypotension, which are not eliminated by the appointment of special drugs and are combined with a violation of the fetus.

In a planned manner, a cesarean section is performed when a partial placenta previa is combined with another pathology, even in the absence of bleeding.

If a pregnant woman with partial placenta previa carried the pregnancy to term, in the absence of significant bleeding, it is possible that childbirth will occur naturally. With the opening of the cervix by 5-6 cm, the doctor will finally determine the variant of placenta previa. With a small partial presentation and slight bleeding, an opening of the fetal bladder is performed. After this manipulation, the fetal head descends and compresses the bleeding vessels. The bleeding stops. In this case, the completion of childbirth in a natural way is possible. With the ineffectiveness of the measures taken, childbirth is completed promptly.

Unfortunately, after the birth of a child, the risk of bleeding remains. This is due to a decrease in the contractility of the tissues of the lower segment of the uterus, where the placenta was located, as well as the presence of hypotension and anemia, which have already been mentioned above. In addition, it has already been said about the frequent combination of presentation and dense attachment of the placenta. In this case, the placenta after childbirth cannot completely separate from the walls of the uterus on its own, and it is necessary to conduct a manual examination of the uterus and separation of the placenta (the manipulation is performed under general anesthesia). Therefore, after childbirth, women who had placenta previa remain under the close supervision of hospital doctors and must carefully follow all their recommendations.

Infrequently, but still there are cases when, despite all the efforts of doctors and a caesarean section, the bleeding does not stop. In this case, it is necessary to resort to the removal of the uterus. Sometimes this is the only way to save a woman's life.

Precautionary measures

It should also be noted that with placenta previa, one should always keep in mind the possibility of developing severe bleeding. Therefore, it is necessary to discuss with the doctor in advance what to do in this case, which hospital to go to. Staying at home, even if the bleeding is light, is dangerous. If there is no prior agreement, you need to go to the nearest maternity hospital. In addition, with placenta previa, you often have to resort to blood transfusions, so if you have been diagnosed with such a diagnosis, find out in advance which of your relatives has the same blood type as you and get their consent to donate blood for you if necessary (the relative must pre-test for HIV, syphilis, hepatitis).

You can arrange in a hospital where you will be observed so that your relatives donate blood for you in advance. In this case, it is necessary to enlist a guarantee that the blood is used specifically for you - and only if you do not need it, it will be transferred to a general blood bank. It would be ideal for you to donate blood for yourself, but this is only possible if your condition does not cause concern, all indicators are normal and there is no spotting. You can donate blood for storage multiple times during your pregnancy, but you also need to ensure that your blood is not used without your knowledge.

Although placenta previa is a serious diagnosis, modern medicine allows you to endure and give birth to a healthy child, but only if this complication is diagnosed in a timely manner and all doctor's prescriptions are strictly observed.

When everything is over and you and your baby are at home, try to organize your life properly. Try to rest more, eat right, be sure to walk with the baby. Do not forget about multivitamins and drugs for the treatment of anemia. If possible, do not refuse breastfeeding. This will not only lay the foundation for the health of the baby, but also speed up the recovery of your body, because. stimulation of the nipple by sucking causes the uterus to contract, reducing the risk of postpartum hemorrhage and uterine inflammation. It is desirable that at first someone helps you in caring for the child and household chores, because your body has suffered a difficult pregnancy, and it needs to recover.

Evgenia Nazimova
obstetrician-gynecologist, Moscow

12/17/2007 00:07:52, Olga

Doctors do not like this diagnosis and try to convince her to terminate the pregnancy at the beginning, when the presentation was established on the first ultrasound. and do not say that everything can change. I liked the article, detailed, necessary, at one time I bit by bit collected any information about this complication. In conclusion, the article is very optimistic. very necessary words about the possibility of giving birth to a healthy child no matter what. I want another child and I hope this complication does not tend to recur.

The article is interesting, but leaves no hope for women with previa that the placenta will return to its normal position by 30 weeks. I had bleeding at 22 weeks, the diagnosis was full presentation. So in a month the placenta rose by 6 cm from the internal pharynx (the lower limit of the norm). So I would like to say that presentation is not a final diagnosis at the beginning of the 2nd trimester and it is not necessary to go to the hospital before delivery.

07/10/2006 13:21:58, Katyusha

But the diagnosis of "placenta previa" is not a reason for panic - it only means that the expectant mother needs to take care of herself and not neglect the doctor's recommendations.

In the normal course of pregnancy, the placenta (an organ that provides blood supply, and with it oxygen and nutrients to the fetus) is usually located in the bottom (upper part of the uterus) or on the walls of the uterus, more often along the back wall, with the transition to the side walls, those. in those areas where the walls of the uterus are best supplied with blood. On the anterior wall, the placenta is located somewhat less frequently, since the anterior wall of the uterus undergoes significantly more changes than the posterior one. In addition, the location of the placenta on the back wall protects it from accidental injury.

Placenta previa is a pathology in which the placenta is located in the lower sections of the uterus along any wall, partially or completely blocking the area of \u200b\u200bthe internal pharynx - the area of the exit from the uterus. If the placenta only partially covers the area of the internal pharynx, then this is an incomplete presentation, which is noted with a frequency of 70-80% of the total number of presentations. If the placenta completely covers the area of the internal os, then this is called complete placenta previa. This option occurs with a frequency of 20-30%.

There is also a low location of the placenta, when its edge is at a lower level than it should be in the norm, but does not cover the area of \u200b\u200bthe internal pharynx.

The reasons

The most common causes of the formation of a low location or placenta previa are pathological changes in the inner layer of the uterus (endometrium) due to inflammation, surgical interventions (curettage, caesarean section, removal of myoma nodes - nodes of a benign uterine tumor, etc.), multiple complicated births. In addition, violations of the attachment of the placenta may be due to:

existing uterine fibroids;
endometriosis (a disease in which the inner lining of the uterus - the endometrium - grows in uncharacteristic places, for example, in the muscle layer);
underdevelopment of the uterus;
isthmic-cervical insufficiency (a condition in which the cervix does not perform its obturator function, it opens slightly and the fetal egg is not held);
inflammation of the cervix;
multiple pregnancy.

Due to these factors, the fetal egg entering the uterine cavity after fertilization cannot be implanted in the upper sections of the uterus in a timely manner, and this process is carried out only when the fetal egg has already descended into its lower sections. It should be noted that placenta previa is more common in re-pregnant women than in primiparas.

How does placenta previa manifest itself?

The most common manifestation of placenta previa is recurrent bleeding from the genital tract. Bleeding can occur during various periods of pregnancy, starting from its earliest terms. However, most often they are observed in the second half of pregnancy. In the last weeks of pregnancy, when uterine contractions become more intense, bleeding may increase.

The cause of bleeding is the repetitive placental abruption, which is not able to stretch following the stretching of the uterine wall during the progression of pregnancy or the onset of labor. In a normal location, the placenta is located in areas of the uterus that are least stretched. In this case, the placenta partially exfoliates, and bleeding occurs from the vessels of the uterus. The fetus does not shed blood. However, he is threatened by oxygen starvation, since the exfoliated part of the placenta is not involved in gas exchange.

The provoking factors for the occurrence of bleeding in placenta previa or its low attachment can be: physical activity, a sharp coughing movement, vaginal examination, sexual intercourse, increased intra-abdominal pressure with constipation, thermal procedures (hot bath, sauna).

With complete placenta previa, bleeding often appears suddenly, i.e. without provoking factors, without pain, and can be very abundant. Bleeding may stop, but reappear after some time, or may continue in the form of scanty discharge. In the last weeks of pregnancy, bleeding resumes and / or increases.

With incomplete placenta previa, bleeding can begin at the very end of pregnancy, but more often this occurs at the beginning of labor. The amount of bleeding depends on the size of the placenta previa. The more placental tissue is present, the earlier and more bleeding begins.

Recurrent bleeding during pregnancy, complicated by placenta previa, in most cases leads to the development of anemia - a decrease in the amount of hemoglobin in the blood.

Pregnancy with placenta previa is often complicated by the threat of interruption; this is due to the same reasons as the occurrence of an incorrect location of the placenta. Preterm labor most often occurs in patients with complete placenta previa.

Pregnant women with placenta previa are characterized by low blood pressure, which occurs in 25-34% of cases,

The management of pregnant women in an obstetric hospital provides, if necessary, the use of drugs that ensure the elimination of the contractile activity of the uterus.

Preeclampsia (a complication of pregnancy characterized by disruption of all organs and systems of the expectant mother, deterioration of uteroplacental circulation, more often manifested by an increase in blood pressure, the appearance of protein in the urine, edema) is also no exception for pregnant women with placenta previa. This complication, which occurs against the background of dysfunction of a number of organs and systems, as well as with symptoms of blood clotting disorders, significantly worsens the nature of recurrent bleeding.

Placenta previa is often accompanied by fetal placental insufficiency (the fetus does not receive enough oxygen and nutrients) and fetal growth retardation. The exfoliated part of the placenta is switched off from the general system of the uteroplacental circulation and does not participate in gas exchange. With placenta previa, an incorrect position of the fetus (oblique, transverse) or breech presentation is often formed, which, in turn, are accompanied by certain complications.

What is "placental migration"

In obstetric practice, the term "placental migration" is widely rooted, which, in fact, does not reflect the real essence of what is happening. The change in the location of the placenta is carried out due to a change in the structure of the lower segment of the uterus during pregnancy and the direction of growth of the placenta towards a better blood supply to the sections of the uterine wall (towards the bottom of the uterus) compared to its lower sections. A more favorable prognosis in terms of placental migration is noted when it is located on the anterior wall of the uterus. Usually the process of "migration of the placenta" occurs within 6 weeks and is completed by 33~34 weeks of pregnancy.

Diagnostics

Identification of placenta previa is not particularly difficult. The presence of placenta previa may be indicated by complaints of a pregnant woman about bleeding. In this case, recurrent bleeding from the second half of pregnancy, as a rule, is associated with complete placenta previa. Bleeding at the end of pregnancy or at the beginning of labor is more often associated with incomplete placenta previa.

In the presence of bleeding, the doctor will carefully examine the walls of the vagina and cervix using mirrors to exclude trauma or pathology of the cervix, which may also be accompanied by the presence of spotting.

A vaginal examination of a pregnant woman also easily reveals clear diagnostic signs indicating an incorrect location of the placenta. Currently, the most objective and safest method for diagnosing placenta previa is ultrasound, which allows you to establish the very fact of placenta previa and the variant of placenta previa (complete, incomplete), determine the size, structure and area of the placenta, assess the degree of detachment, and also obtain an accurate concept of placental migration.

If the ultrasound revealed a complete placenta previa, then a vaginal examination is not performed at all, since it can provoke bleeding. The criterion for the low location of the placenta in the III trimester of pregnancy (for a period of 28-40 weeks) is the distance from the edge of the placenta to the area of the internal os 5 cm or less. Placenta previa is indicated by the presence of placental tissue in the area of the internal os.

The nature of the location of the placenta in the II and III trimesters of pregnancy (up to 27 weeks) is judged by the ratio of the distance from the edge of the placenta to the area of the internal os with the diameter of the fetal head.

If an incorrect location of the placenta is detected, a dynamic study is carried out to control its "migration". For these purposes, at least three echographic control (ultrasound) is required during pregnancy at 16, 24-26 and 34-36 weeks.

Ultrasound should be performed with moderate filling of the bladder. With the help of ultrasound, it is also possible to determine the presence of an accumulation of blood (hematoma) between the placenta and the wall of the uterus during placental abruption (in the event that there was no outflow of blood from the uterine cavity). If the site of placental abruption occupies no more than 1/4 of the area of the placenta, then the prognosis for the fetus is relatively favorable. If the hematoma occupies more than 1/3 of the area of the placenta, then most often this leads to the death of the fetus.

Features of pregnancy and childbirth

The nature of pregnancy in women with placenta previa depends on the severity of bleeding and the amount of blood loss.

If there are no spotting in the first half of pregnancy, then the pregnant woman can be at home under outpatient control in compliance with a regimen that excludes the action of provoking factors that can cause bleeding (restriction of physical activity, sexual activity, stressful situations, etc.).

Observation and treatment at a gestational age of more than 24 weeks is carried out only in an obstetric hospital in any case, even in the absence of spotting and normal health.

Treatment aimed at continuing the pregnancy up to 37-38 weeks is possible if the bleeding is not heavy, and the general condition of the pregnant woman and the fetus is satisfactory. Even despite the cessation of bloody discharge from the genital tract, a pregnant woman with placenta previa can under no circumstances be discharged from the hospital before delivery.

Management of pregnant women in an obstetric hospital includes:

observance of strict bed rest;
if necessary, the use of drugs that ensure the elimination of the contractile activity of the uterus;
treatment of anemia (reduced amount of hemoglobin) and fetal placental insufficiency.

In the event that the pregnancy has been carried to 37-38 weeks and placenta previa persists, depending on the situation, the optimal method of delivery is chosen on an individual basis.

The absolute indication for elective caesarean section is complete placenta previa. Childbirth through the natural birth canal in this situation is impossible, since the placenta that overlaps the internal os does not allow the presenting part of the fetus (this may be the fetal head or pelvic end) to be inserted into the entrance to the pelvis. In addition, in the process of increasing uterine contractions, the placenta exfoliates more and more, and the bleeding increases significantly.

In case of incomplete placenta previa and in the presence of concomitant complications (breech presentation, abnormal position of the fetus, scar on the uterus, multiple pregnancy, severe polyhydramnios, narrow pelvis, age of the primiparous over 30 years old, etc.), a caesarean section is also performed in a planned manner.

If the above concomitant complications are absent and there is no spotting, then the doctor waits until the onset of independent labor and opens the fetal bladder. In the event that, after opening the fetal bladder, bleeding nevertheless began, the issue of performing a caesarean section is decided.

If, with incomplete placenta previa, bleeding occurs before the onset of labor, then the fetal bladder is also opened. The necessity and expediency of this procedure is due to the fact that when the membranes are opened, the fetal head is inserted into the entrance to the pelvis and presses the exfoliated part of the placenta against the wall of the uterus and pelvis, which helps to stop further placental abruption and stop bleeding. If bleeding after opening the fetal bladder continues and / or the cervix is immature, then a caesarean section is performed. In case of stopping bleeding in the absence of complications, it is possible to conduct labor through the natural birth canal.

Bleeding can begin in the early stages of the development of labor from the moment of the first contractions. In this case, the fetal bladder is also opened.

Thus, vaginal delivery with incomplete placenta previa is possible if:

bleeding stopped after the opening of the fetal bladder;
mature cervix;
labor activity is good;
there is a cephalic presentation of the fetus.

However, caesarean section is one of the most frequently chosen methods of delivery by obstetricians in placenta previa and is performed with this pathology with a frequency of 70-80%.

Other typical complications in childbirth with incomplete placenta previa are weakness of labor and insufficient supply of oxygen to the fetus (fetal hypoxia). A prerequisite for conducting labor through the natural birth canal is constant monitoring of the condition of the fetus and the contractile activity of the uterus; sensors are attached to the woman's stomach, which are connected to a device that records the fetal heartbeat and the presence of contractions, these parameters are recorded on a tape or projected onto a monitor.

After the birth of a child, bleeding may resume due to a violation of the process of separation of the placenta, since the placental site is located in the lower sections of the uterus, the contractility of which is reduced.

Abundant bleeding often occurs in the early postpartum period due to a decrease in uterine tone and damage to the extensive vasculature of the cervix.

Prevention of placenta previa is the rational use of contraceptives, the exclusion of abortion, the early detection and treatment of various inflammatory diseases of the reproductive system and hormonal disorders.

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