Pregnancy age by last menstruation calculator. Pregnancy terms: obstetric and embryonic - how to determine and not get confused in terms

It is very difficult to calculate the gestational age to the nearest day and perhaps only if ovulation was specifically monitored using ultrasound. But these procedures are carried out only in the treatment of infertility. And therefore, the day of conception often remains a mystery even for the couple themselves, not to mention the doctors.

And yet, are there any calendar methods for calculating conception, is it possible to calculate the gestational age based on the menstrual cycle and the day of delay? What procedures and tests help in diagnosis and calculations? You will read about all this in the article.

calendar methods

If sexual intercourse does not occur too often, then it is quite possible that a woman will remember exactly on which day that same nimble sperm cell entered her body, which subsequently fertilized the egg. This is also possible if a woman scrupulously measures her basal temperature for several cycles and knows how to use the resulting charts with temperature values. She reports this most calculated day to the doctor, after ascertaining her pregnancy. However, the doctor, having learned when the last monthly patients were, calls the period 2 weeks more. How can this be and what to believe?

The fact is that doctors consider the obstetric period, and it depends only on the first day of the last menstruation. It turns out that pregnancy begins on the first day of menstruation, although this is not the case, of course. But this calculation method is quite accurate. And according to the same method, the estimated date of birth is calculated: 280 days are added to the first day of the last menstruation, or 3 months are taken away and 7 days are added (according to the Negele formula).

If the exact day of ovulation is known, then we can add not 280 days to the first day of the menstrual cycle, but 264. And in this way we will also find out the estimated due date. Well, pregnancy can begin to count from the day of ovulation. But again, doctors do not conduct such a calculation, and these values ​​\u200b\u200bare not taken into account.

Ultrasound procedure

Ultrasound has been actively used for many years to diagnose fetal development. And with the help of ultrasound, the gestational age is specified. Particularly accurate in this regard are studies conducted in the first weeks of pregnancy (up to 8 weeks). During this period, all healthy embryos develop in the same way, and the gestational age according to the size of the fetus is set exactly up to the day. The longer the term - the more mistakes, since the children begin to show individuality in a sense - one head may be slightly larger than it should be at a certain period, and the other baby has a growth slightly below its age limits. If the deviations are insignificant - for a week or less, then their doctors do not take into account, as a rule, and nothing needs to be treated. Estimated term is set on the basis of measurement data of the coccygeal-parietal size. The result is obtained using a table.

If there is a developmental delay of 2 weeks or more, for all that, there is confidence in the absence of an error in setting the gestational age, the doctor makes a diagnosis of "intrauterine growth retardation of the fetus." It is impossible to "cure" her. Everything that is done in a hospital is only a preventive, and not too pronounced, effect. Good nutrition, a healthy lifestyle, walks, quiet leisure - that's what is much more important.

Gynecological examination

Many women go to the gynecologist on the very first day of the delay, or even earlier, in the hope that the doctor will be able to say for sure whether they are in a position or not. But this is not possible, unfortunately. The uterus may be slightly enlarged before menstruation. The growth of the uterus due to the development of the fetus in it begins noticeably from the end of the first trimester. At 5-6 weeks (that is, in the second or third week of delayed menstruation), the uterus is slightly larger than usual, the volume can be compared with a chicken egg. At 8 weeks, the uterus is already the size of a goose egg, and at 10 weeks it is about the size of a woman's fist. Again, gynecological examinations are the more accurate for determining the gestational age, the smaller it is.

Date of first movement

All gynecologists inspire their patients, expectant mothers, that they must remember the day when they first felt the baby inside them, that is, they felt his movements. It is believed that in pregnant women for the first time this occurs exactly at 20 weeks of pregnancy, and in pregnant women again - at exactly 18 weeks. This date must be entered into the dispensary card of a pregnant woman and taken into account when determining the expected date of birth. Although, if you believe the statements of many expectant mothers, the timing of the first movements does not always coincide with the "book". I would also like to reassure a little hyper-responsible expectant mothers who are afraid that they will not notice the first movements, thereby confusing the doctor when setting the date of birth, which can lead to overwearing. Firstly, re-carrying is determined according to the result of Doppler and according to some ultrasound indicators (maturity of the placenta, the volume of amniotic fluid, etc.). And secondly, the first movements are really very light, but quite noticeable. It is impossible not to notice the movement if you are in a horizontal position, especially on your back.

Uterine length

From about the second trimester of pregnancy, and sometimes even earlier, gynecologists evaluate the development of the fetus along the length of the uterus. It is measured with a centimeter tape, the expectant mother lies on the couch. Each week adds about 1 centimeter. There is another measurement technique, many doctors use the corresponding tablets, and they can also be found in obstetrics and gynecology manuals.

12 weeks - the uterus is on the upper edge of the womb

14 weeks - the uterus is two fingers above the womb

16 weeks - the bottom of the uterus is felt between the navel and the womb

20 weeks - the fundus of the uterus is two fingers below the navel

24 weeks - uterus at the level of the navel

28 weeks - the fundus of the uterus is 2 fingers above the navel

32 weeks - between the navel and the xiphoid process (the shortest part of the sternum), length 28-30 cm

36 weeks - the bottom of the uterus at the level of the xiphoid process, "supports" the ribs, length 32-34 cm

40 weeks - before childbirth, the uterus drops to the level of 32 weeks, as the baby's head (or other presenting part of the fetus) moves lower into the pelvis, preparing to exit.

In addition to the length of the uterus, the volume of the abdomen is also taken into account, but these dimensions are already more variable, do not always show the true state of affairs and help calculate the gestational age by weeks. The volume of the abdomen is measured at the level of the navel. So in a woman with normal weight before and during the bearing of a child, the volume of the abdomen at 32 weeks will be approximately equal to 85 centimeters, and by the end of pregnancy it reaches 90-100 cm. Such an increase is associated with the rapid weight gain of the child.

The length of the uterus not only helps to verify the normal development of the fetus, the gestational age, but also to detect such pathologies as polyhydramnios or oligohydramnios and others in time.

Heart tones

The heart of the child begins to beat already at a period of 4.5 weeks, that is, 2-3 weeks after the start of a delay in menstruation in a woman. Heartbeats are visible on ultrasound, and this is the main sign that the embryo is alive and developing. Later, the heartbeat begins to be heard by the doctor through the outer wall of the uterus. But you can only hear heart tones not at 10-12 weeks, but later - at about the same time as you feel the first movements. The heartbeat is heard with the help of an obstetric stethoscope - a special tube that the doctor applies to the patient's stomach. A heartbeat can be poorly heard for several reasons. The most "harmless" of them - the placenta, which is located on the front wall of the uterus, and thereby muffles the sound, and significant deposits of fat on the abdominal wall. More seriously - polyhydramnios, chronic hypoxia. The longer the period, the more clearly the heart rhythms are heard.

Chorionic gonadotropin level

This method of determining the duration of pregnancy is used, as a rule, in the first weeks. But it doesn't always give accurate results. A blood test is taken from a vein.

Approximate hCG values ​​for the first weeks of pregnancy:

• 2 - 25-300 mU/ml
• 3- 1500-5000 honey/ml
• 4 - 10000 - 30000 mU/ml
• 5 - 20000 - 100000 mU/ml

As you can see, the values ​​can vary greatly, so there may be errors in the calculations. This analysis is ideally used not for calculating the timing, but for early diagnosis of pregnancy and its possible pathologies.

We have given the main ways to correctly calculate the gestational age. Some of them you can try on your own, others require medical intervention and some procedures.

Gestational age- one of the main components that a gynecologist needs to know about for the proper management of pregnancy. After all, on the basis of this, the doctor will prescribe the necessary examinations, tests, planned ultrasound scans, monitor intrauterine growth and fetal development, and identify possible violations in time. In addition, the determination of the term allows you to fairly accurately calculate the date of birth and the date of maternity leave. The woman herself needs to know the gestational age in order to mentally prepare for childbirth, to have time to prepare a room or a corner for the future baby, to purchase all the necessary accessories and clothes for him.

In the article, we will consider how to determine the gestational age.

Calculate by monthly

The gynecologist first of all asks a woman who has come to register at the antenatal clinic the question of when her last menstruation began. It is from this date that he begins to keep a record, despite the fact that fertilization has not yet occurred at this time. It is known that the fertilization of the egg occurs on the day of ovulation, which occurs in the middle of the menstrual cycle. This method of determining the gestational age is called "obstetric".

An online calculator will help determine the term:

How to determine by the date of conception

It is known that conception occurs only during ovulation within a day after the release of the egg from the follicle. And the viability of spermatozoa in the female genital tract is up to 3 days. It turns out that the date of sexual intercourse does not always coincide with the date of conception.

Ovulation occurs in the middle of the menstrual cycle. A woman who monitors her menstrual cycle can quite accurately calculate the onset of ovulation in herself. In addition, many at this time have characteristic signs: aching pains in the lower abdomen, breast swelling, irritability, copious vaginal discharge, increased sexual desire.

It is worth noting that only those women who have a regular menstrual cycle can determine the gestational age by the date of conception.

Online calculator:

(calculation will take a few seconds)

How to calculate by ultrasound

It is possible to find out the gestational age by the results of an ultrasound examination (ultrasound). It is determined according to the size of the fetus. The first ultrasound of the expectant mother is carried out at 12-14 weeks, but at this time it is no longer possible to accurately determine the period, since the development of the fetus in each woman occurs individually. Finding out the age of the fetus by ultrasound with an accuracy of one day is possible only in the first weeks after conception.

Determination of the entrance of the examination by a gynecologist

A gynecologist can determine a woman's gestational age by the size of her uterus during a pelvic exam. At 5-6 weeks, the size of the uterus can be compared with a chicken egg, at 8 weeks - with a goose egg. Later, it will be more difficult to determine how many weeks a woman has by the size of her uterus.

Find out the date by the first movement of the fetus

A woman begins to feel fetal movements in the first pregnancy at 20 weeks, in the second - at 18 weeks. But this method does not always allow you to set a deadline, since some expectant mothers may feel the first fetal movements earlier or later than the indicated weeks - some, due to the structural features of the body, cannot feel the fetal movements, others confuse the work of the intestines (increased flatulence) with movements.

Determine by hCG

Human chorionic gonadotropin (hCG)- one of the most important indicators indicating the onset of pregnancy and its normal development. The hormone begins to be produced in the female body after the implantation of the embryo into the wall of the uterus. The level of hCG in the blood allows you to find out the approximate age of the fetus. With multiple pregnancy, the level of the hormone in the blood increases in proportion to the number of fetuses.

pregnancy calculators

The calculator calculates your pregnancy based on your last period. The gestational age is obtained in "obstetric" weeks.

As a rule, every pregnant woman has her own calendar, where she enters all the necessary data, outlines important dates, and takes notes. With its help, the gestational age is usually calculated.

Given the nine-month duration of this period, calculations on a piece of paper seem to be a very routine task. But modern women live at a great time - they are not at all obliged to keep such a calendar and do tedious arithmetic, unless, of course, they are so sentimental that they decide to keep their weekly notes as a memory of the wonderful time of gestation. You can safely entrust the program to take care of calculating the gestational age. After all, for those who prefer to spend their free hours on activities that are much more useful for the future baby and his mother, there are numerous virtual services like this one (we hint at our calculator).

What do you need to calculate the gestational age?

In order to calculate the gestational age right now, you only need to remember the date when the last menstruation began and enter it in the appropriate form fields. This number is the starting point of your pregnancy. We are talking about the so-called "obstetric weeks" - all over the world it is customary to count pregnancy in this way, although fertilization occurs only in the middle of the cycle. This measure is necessary for the convenience of doctors, but often causes surprise and misunderstanding among patients.

It is worth noting - during an ultrasound examination of the fetus, you will encounter the fact that the known gestational age can be calculated differently - by the weeks of the fetus's life, that is, from the day of conception. You may even find an entry on the ultrasound results sheet that lists both dates. In order not to be embarrassed by such contradictions, feel free to ask the doctors what kind of gestational age we are talking about, real or obstetric?

It is very important to emphasize that even if you know the exact date of conception of the baby, in order to calculate the gestational age using the calculator, you need to use the date of the last menstruation. If you find it difficult to remember, count 2 weeks ago - with a standard 28-day cycle, ovulation most often occurs on day 14.

I don't remember when I had my period. What to do?

Sometimes it happens that a woman does not know when she had her last period, for example, she does not remember, does not follow the regularity of the cycle, or has just stopped taking contraceptives. If you have no idea what your gestational age is, it can be calculated at. The data obtained in the early stages (up to 12 weeks) have the greatest reliability, when the rate of development of the ovum is still very high and changes are noticeable literally every day. The size of the fetal egg alone, without taking into account the proportions of the fetus, will tell the doctor a lot. At later dates, errors of up to 2 weeks are possible.

Another very informative method that allows you to calculate the gestational age is biochemical - a study of a woman's blood for the content of hCG - human chorionic gonadotropin. This hormone is produced by the fetal egg and is present in the body only during pregnancy (by the way, it is on its determination in the urine that the well-known instant pregnancy test is based). The content and during a healthy pregnancy is clearly correlated with the timing. It is worth noting that this is far from a routine method that requires a lot of time and money and is used mainly for medical reasons.

It is impossible not to mention that finding out the gestational age, calculating and assuming the probable age of the fetus is within the competence of the obstetrician when conducting a vaginal examination in the early stages. The main object of research in this case will be the uterus and palpation (manual) determination of its size. Of course, we are not talking about absolute accuracy, but the data obtained is quite enough to successfully monitor the health of the expectant mother and fetus.

Questions for the article

On the ultrasound on 06/30/2017, the doctor said nothing was visible, only there was a cyst...

I looked at the test, but I got a negative result. but so...

The lower abdomen hurts periodically, it swells, it hurts the stomach, what can it be ...

Please, from what week can you feel the movement of the fetus? ...

The size of the fetal egg corresponds to 3-4 weeks, according to hCG at 2.02 4539, at 4.02 ...

Pregnancy ... but it's still too early to do the test and there is no delay, but I already ...

The result of hcg is 20.9 mlu/ml. what is my gestational age? last...

Please. The first day of the last menstruation is 04/20/2016. (conception after...

Accordingly, the period should be 8 weeks, but they put 4-5 on ultrasound ...

Discharge (brownish), what could that mean?...

The pregnancy calculator allows you to calculate the exact due date and find out what week of pregnancy you are currently in, as well as the expected date of delivery. To calculate, select the date of the first day of your last period at the top of the calculator and click on the "Calculate" button. The calculator will then automatically display your current pregnancy week and expected due date.

For each week of pregnancy, two exact dates are displayed: the start day and the end day. The interval between them is exactly 7 days. You can scroll through the weeks of pregnancy using the arrows. The full list of weeks from 1st to 40th is at the very bottom of the calculator. By clicking on them, you can also scroll through the slider for the desired week. The trimester of pregnancy to which each week belongs is indicated by Roman numerals at the bottom (near the slider) and in the upper right corner of the cells (in the full list of weeks). Also, the trimesters are marked in pink, orange and blue, respectively. In general, the very concept of pregnancy trimesters is rather arbitrary and their boundaries are not clearly defined. We took as a basis the most common classification, in which the second trimester begins at the 14th week and ends at the 28th. Only your obstetrician-gynecologist can calculate trimesters more accurately after an ultrasound scan.

In the images you can see a rough illustration of the development of the baby inside the womb for each week. To the left of the images is a summary of the fetal growth for that week. For more complete and detailed information, you can find by clicking on the "More" link, which is located under each description.

Method for calculating the gestational age

The calculator calculates the so-called "obstetric" gestational age. It differs from the actual date by about two weeks. This calculation method is used in gynecology, because. it is very difficult to calculate the exact day of conception. Therefore, the calculation is based on the first day of the last menstruation, the date of which, as a rule, every woman remembers. 280 days or 40 weeks are added to this day. Thus, the first two weeks of the obstetric period you are not yet pregnant, because. ovulation has not yet occurred (based on an average menstrual cycle of 28 days). This method is not completely accurate because some women ovulate late or early. But, in general, for most expectant mothers, such a calculation turns out to be quite accurate.

In any case, we draw your attention to the fact that the pregnancy calculator allows you to calculate the term using the most general formula, which does not take into account the individual characteristics of your body. It cannot be used for self-diagnosis or any other medical purposes, since the results of its calculations are for informational purposes only. All precise calculations and any other manipulations should be done only by your attending physician.

Congratulations!

Few things compare to the joy when a pregnancy test shows a positive result! After realizing the wonderful news that you will soon become a mother, you will begin to think about practical issues. One of these questions is how to find out the date of birth?

Start with

Cycle duration 21 days. 22 days 23 days 24 days 25 days 26 days 27 days 28 days 29 days 30 days 31 days 32 days 33 days 34 days 35 days 36 days 37 days 38 days 39 days 40 days

Defining it is not as easy as it might seem. Most moms-to-be don't realize they're pregnant until the first missed period, by which time the pregnancy can be up to five weeks. This means that it is not enough to simply count nine months from the date of the pregnancy test, even if you try and take into account the weeks that have passed since the last ovulation.

It will be possible to determine the exact date of birth of your unborn child only if you remember exactly the day of the ovulatory cycle at the time of fertilization.

HOW TO USE THE CALCULATOR TO DETERMINE THE DATE OF BIRTH OF A CHILD

You may not know that menstruation and ovulation are considered the first two weeks of pregnancy. Therefore, it is not surprising that the calculations can be difficult, especially if your cycle is longer or shorter than the average (28 days).

Although pregnancy usually lasts 40 weeks, the date of delivery can depend on various factors. Our calculator takes into account your last period start date and cycle length to quickly calculate an estimated due date based on your cycle length.

If you know the exact date of conception, enter it. The calculator takes into account the first two weeks that fall on menstruation and ovulation.

• 1.First specify first day of your last period, as well as the average duration of your cycle. This is the number of days from the first day of one period to the last day before the start of the next period. If you know which one the day conception occurred, choose this option as an alternative.
• 2. Enter relevant dates into a calculator.
• 3. Then press To know!

Remember that the calculator calculates an approximate date, not an exact date. After all, every pregnancy is different.

WHAT TO DO WHEN YOU KNOW YOU ARE PREGNANT

Having calculated the date of birth, you will know the approximate date the baby will be born, and you can start preparing for this.

If you haven't already, start by making an appointment with your doctor, who will confirm your pregnancy with a blood test and physical examination, and help you determine a more accurate due date.

At each follow-up visit, the doctor will determine the size of your uterus and monitor your baby's development. The highlights of these examinations will be when you first hear the baby's heartbeat and also when you see it on the sonogram. As your pregnancy progresses, your due date may change.

Remember that throughout pregnancy, first of all, you should listen to the advice of a doctor. However, there are some things you can do yourself. Check out the rest of our website for more information.