Is it possible to know the exact gestational age. Calculation of gestational age, methods for determining the period by week, calculator

10.07.2019

Determining pregnancy in the early stages is important for a woman. So, almost 50% of embryos die in the first two to three weeks from the moment of conception. This is due to the fact that the fetus is defenseless against infection, which may be in the mother's body due to bad habits and other negative factors. Taking medications, smoking, prolonged exposure to the sun and drinking alcohol are the most common causes of embryonic death in the first months of pregnancy. Many women may not be aware of their situation and continue to lead a life that is fatal to the development of the embryo.

Determination of pregnancy in the early stages is also necessary for those women who plan to have an abortion. Since an abortion in the later stages can lead to infertility in the future, and serious complications. Medical abortions are done during the first four to six weeks of pregnancy, and vacuum aspiration or mini-abortions are done within 20 days after a missed period and confirmation of pregnancy. A classic abortion (curettage) is done before the 12th week of pregnancy. But the optimal period for abortion and maintaining the health of a woman is considered to be 6-8 weeks.

The onset of pregnancy is determined by various signs, both in appearance and in the behavior of the pregnant woman. Frequent mood changes, vulnerability, change in taste preferences, increased sensitivity, nausea (especially in the morning), swelling of the limbs, delayed menstruation and swelling of the mammary glands may indicate early pregnancy.

Methods for determining the gestational age

Methods for determining the duration of pregnancy allow you to determine how much time is left before childbirth and how the unborn child develops. Let's look at the most popular methods for determining the duration of pregnancy.

According to menstruation and according to the results of examination by a gynecologist. In early pregnancy, the uterus enlarges to the size of a chicken egg.
According to ultrasound, the accuracy of determining pregnancy using ultrasound is quite high in the first trimester.
By ovulation - the gestational age can be determined by the date of the proposed conception, adding 14 days to it. According to this method, the date of birth is also determined. To do this, three months and seven days are counted from the date of ovulation.
By bimanual examination - this method allows you to determine the gestational age by probing the position of the uterus. In the first trimester, the uterus is located in the pelvic area, and starting from the second trimester, it is palpable above the bosom.

Test for determining the duration of pregnancy

The test for determining the gestational age is a modern method to find out the period before going to the gynecologist. The most popular test among expectant mothers to determine the duration of pregnancy is Clearblue. The test is easy to use and gives results with 99% accuracy.

Clearblue with gestational age

Clearblue Pregnancy Due Date is a digital test that shows a double result on a special Smart Dual Sensor touch display. So, with the help of a test, you can not only confirm pregnancy, but also find out its term. Let's take a look at the benefits of the Clearblue test.

Now there is no need to look at the strips on the express test, as the digital display will show a reliable result that will last for 24 hours.
Clearblue is the only test of its kind that provides information about the gestational age, that is, the amount of time elapsed since conception.
The test gives a 99% accurate result from the first day of the delay.
The test is very simple and easy to use.
Clearblue has been approved by obstetricians and gynecologists worldwide.

Determination of the child's gestational age

Determining the gestational age of a child is carried out by several methods. Some methods are based on the date of the last menstruation and the duration of the delay, the second on the signs of pregnancy that a woman has, and still others make it possible to find out the gestational age using a digital test. Another way to determine the gestational age of a child is to undergo a gynecological examination or ultrasound. Each woman decides for herself which method to use. On average, after conception, it takes about seven days for the sperm to fertilize the egg. That is why, many women are guided by the period of ovulation. Please note that it is recommended to plan pregnancy according to the timing of ovulation.

Determining the gestational age by ultrasound

Determining the gestational age by ultrasound is one of the most reliable ways. The use of ultrasound in the first weeks of delayed menstruation allows you to accurately diagnose the timing of the onset of pregnancy. Ultrasound is performed not only to determine the timing of pregnancy, but also to control the course of pregnancy and the development of the baby. Many gynecologists argue that the period of up to 6 weeks is considered the optimal period for a reliable diagnosis of pregnancy. Diagnosis of gestational age by ultrasound in a later period will be difficult.

Ultrasound results in the first weeks after conception are based on the length of the fetus. The gynecologist measures the length of the fetus and compares the data with the table values. This allows you to accurately determine the duration of pregnancy and control its course. Throughout pregnancy, a woman should do control ultrasounds so that the gynecologist can monitor the development of the child and, if necessary, prevent the development of pathologies.

Determining the gestational age by week

Determining the gestational age by weeks is the task of a gynecologist. Knowing the exact gestational age, which is calculated in weeks, the gynecologist controls the development of the child and throughout the entire period of pregnancy. In addition, depending on the period, the doctor prescribes the delivery of certain tests and studies that will help prevent the development of pathologies and complications in the child.

Weeks of pregnancy are obstetric (which is monitored) and embryonic. The obstetric period is 40 weeks, and the embryonic period is 38 weeks. To determine the exact period, the gynecologist monitors the symptoms of pregnancy and the development of the embryo.

Determining the duration of pregnancy by menstruation

Determining the gestational age by menstruation is most often used, since this method is quite simple and effective. When examined by a gynecologist and setting the gestational age, the doctor learns about the date of the last menstruation and the duration of the cycle. These data allow you to determine the duration of pregnancy by menstruation. Gynecologists use the method of counting pregnancy from the first day of the last menstruation. Since it is almost impossible to establish the exact date of conception, and menstruation is the only guideline.

When determining the gestational age, gynecologists use a calculation formula based on a menstrual cycle of 28 days. This suggests that ovulation occurred on the 14th day after the start of menstruation. But this formula is not always accurate, as not all women have a regular menstrual cycle. Therefore, the determination of the term has an error. Gynecologists distinguish between two stages of pregnancy, the first is obstetric (from the first to the last day of menstruation), and the second is embryonic (from the date of fertilization and ovulation).

Table for determining the gestational age

The table for determining the gestational age allows you to visually look at the expected date of birth and the gestational age. The table is based on the results of analyzes and gynecological examinations. There are several criteria that serve as source material in the pregnancy determination table: the size of the fetus, the date of the last menstruation, and the results of diagnostics.

We offer you a table for determining the duration of pregnancy according to the results of an ultrasound examination, that is, by the size and weight of the fetus. The dimensions and weight of the embryo in the first trimester are not taken into account in the table, as they are too small. Please note that the obstetric weeks of pregnancy are used in the table for determining the gestational age.

Determination of the exact gestational age

Determination of the exact gestational age can be carried out by several methods. Each of them has an error, let's look at the most popular.

Symptomatic - the gestational age is determined by certain symptoms. So, breast enlargement, lack of menstruation and increased sensitivity indicate early pregnancy. True, this method is very controversial, since in some cases the symptoms described above may indicate complications in the female body, and not about pregnancy. That is, the exact method is 50%.
Ultrasound is a popular method for determining the gestational age. The accuracy of ultrasound results in determining the term is 100%.
Digital tests are a modern method for determining the duration of pregnancy. The test accuracy is 99%.
Gynecological examination is the most accurate method for determining the period. With the help of examination and test results, the gynecologist determines the gestational age. The accuracy of this method is 100%

Calendar for determining the duration of pregnancy

The pregnancy calendar is based on the Naegele formula. Nine months and seven days of pregnancy are added to the date of the last menstruation (its beginning) and three months are taken away. Seven more days must be added to the received date, the result obtained is the preliminary date of birth. According to this formula, there is a special calendar.

If you do not trust the calendar method, you can check its effectiveness. Calculate the date of birth according to the calendar and compare it with the one that the gynecologist will say after the examination. Please note that when determining the gestational age, fetal movement is of great importance. It is with the help of the date of stirring that you can calculate the exact date of birth. At the same time, for women who give birth for the first time, 22 weeks are added to the date of stirring, and those who give birth again 20 weeks.

Determining the duration of pregnancy by hCG

Determining the duration of pregnancy by hCG refers to one of the most accurate methods. HCG or human chorionic gonadotropin is a protein hormone that is produced by the membranes of the embryo throughout pregnancy. It is hCG that blocks the processes responsible for the menstrual cycle in the female body and enhances the production of hormones that are responsible for maintaining pregnancy. HCG rises at conception and is one of the reliable signs of pregnancy. The level of hCG rises from the first week of pregnancy, that is, within 14 days after conception. This indicator doubles every day, starting from the 3rd week of pregnancy and up to the 12th week. From the 12th to the 22nd week, the hormone level does not increase, but from the 22nd week it starts to rise again.

The rate of increase in hCG in the blood makes it possible to determine deviations in the development of pregnancy. So, with a frozen or ectopic pregnancy, hCG is below normal. A sharp increase in this indicator indicates a multiple pregnancy or chromosomal diseases. Therefore, the gynecologist, like the pregnant woman herself, should monitor the dynamics of the concentration of hCG in the blood during pregnancy. Let's look at the norms of hCG content and the effect of this hormone on determining the duration of pregnancy.

Days since last menstrual period	Nomes of hCG level for this period honey/ml	Gestational age

Please note that the values indicated in the table are not a standard. So, depending on the characteristics of the woman's body and the course of pregnancy, the norms of hCG also change when determining the duration of pregnancy.

Determining the gestational age by conception

Determining the gestational age by conception involves calculating the period by weeks. On average, pregnancy lasts for 280 days or 40 weeks. Obstetricians determine the gestational age by menstruation and this is called obstetric weeks of pregnancy. But the definition of the gestational age by conception is called the embryonic period, and it is based on the period of ovulation. Each woman conceives at a different ovulation period, so when determining the date of birth by conception, it is recommended to add 38 weeks to the date of the last menstruation.

But do not forget that obstetricians lead their own gestational age, which is different from the embryonic (gestational age at conception). And all tests will have to be taken, focusing on the obstetric gestational age.

Determination of gestational age by ovulation

Determining the gestational age by ovulation is a simple and effective method. Ovulation is the period of menstruation during which pregnancy can occur, as a mature egg is released from the ovary and is ready for fertilization. On average, ovulation occurs on day 14 with a normal menstrual cycle of 28 days, and in women with a long cycle, ovulation occurs between days 15 and 18. To accurately determine the period of ovulation, you can buy a special test or measure basal temperature. But some women can determine ovulation by certain symptoms (pain in the lower abdomen, an increased amount of vaginal discharge, increased sexual desire).

But the most accurate way to determine the gestational age by ovulation is an ultrasound. Ultrasound can accurately determine ovulation. True, regular ultrasound is an expensive pleasure, so other simpler methods are used to determine the timing of pregnancy.

Determining the gestational age by KTR

Determining the gestational age according to KTR is possible only with the help of an ultrasound examination. At the beginning of pregnancy, a woman undergoes an ultrasound, on which measurements of the fetal egg are taken. CTE is the coccygeal-parietal size of the embryo, which can be measured using ultrasound imaging. KTR is the maximum distance from the coccyx to the crown. The KTP indicator is used to determine the exact gestational age during the first trimester. Let's take a look at these metrics:

If the exact gestational age must be determined in the second or third trimester, then other indicators are used instead of KTP. Biparietal size or BDP, that is, the size between the temporal bones, is important. Another indicator for determining the exact gestational age is the circumference of the abdomen of the pregnant woman, the length of the thigh or femur. Let's look at the values \u200b\u200bof these indicators and the gestational age. Fetometric parameters in the second and third trimesters of pregnancy:

Biparietal size, mm	Abdominal circumference, mm	Femur length, mm	Pregnancy period, weeks

All of the above indicators use modern ultrasound machines to determine the gestational age. But, do not forget that the figures may differ from the real ones. So, when measuring CTE, the error can be in the week of pregnancy, and when receiving BDP, the error is up to 11 days.

Formula for determining the gestational age

The formula for determining the duration of pregnancy is used by many women. Let's look at the most accurate and popular formulas.

Negele's formula for determining the date of birth by the last menstruation
To calculate, you need to know the date of the last menstruation and subtract three months and seven days from it.
Jordania formula

The formula itself looks like: X \u003d L + C, the X value is the gestational age in weeks, L is the length of the embryo, and C is the head size measured by the tazomer. Let's put this formula into practice. L - 18 cm, C - 12 cm, that is, X \u003d 18 + 12 \u003d 30 weeks of pregnancy. But according to research, there is an error of 2 weeks in this formula.

Skulsky formula

This formula allows you to accurately determine the duration of pregnancy in the last trimester. So, the formula: X \u003d ((Lx2) -5) / 5, where X is the obstetric gestational age, L is the length of the embryo, 2 is the coefficient that allows you to determine the length of the fetus, 5 in the numerator is the coefficient of the thickness of the walls of the uterus, in the denominator - an indicator from the Haase formula.

Haas formula

A formula that was developed by an obstetrician-gynecologist to determine the intrauterine age of the embryo during the first 20 weeks of pregnancy. In the first 20 weeks, the length of the embryo in cm is equal to the square of the months of pregnancy, in the last 20 weeks - the number of months of pregnancy multiplied by 5.

The accuracy of determining the gestational age

The accuracy of determining the gestational age depends on the method used and the characteristics of the course of pregnancy. To determine the exact date, the expectant mother will have to pass a lot of tests. The most accurate method is considered to be ultrasound, the use of digital tests and a gynecological examination.

Determining the gestational age is important for every woman. Knowing the age of the embryo, the gynecologist can monitor its development, the course of pregnancy and prevent various pathologies and complications. In addition, the exact gestational age allows you to determine the date of the future birth and prepare for the meeting with the baby.

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.

Pregnancy is a very dynamic process, during which the fetus grows and develops, and the woman's body is restructured according to the stage of its development. Therefore, the correct determination of the gestational age is very important for understanding the changes that occur in each period. gestation(pregnancy).

Information For the correct determination of the gestational age, information about the first day of the last menstruation, from which it is considered, is important. This approach is legitimate with a regular menstrual cycle.

Fertilization usually occurs after ovulation(the release of the egg from the ovary, that is, in the middle of the cycle), therefore, this definition of the term is somewhat averaged and differs from the true one by an average of 14-16 days. But since in most cases the exact date of ovulation is unknown (with the exception of in vitro fertilization programs), the calculation from the first day of the last menstruation is most often used.

By date of first movement

You can also take into account the date of the first movement of the fetus. In primiparous, this is usually a period of about 20 weeks, in multiparous -. But fetal movements are a rather subjective sign (especially in the early stages it can be confused with the work of the intestines), so it can only be used as an additional one.

Beyond Data history(the totality of information obtained by interviewing the patient), when determining the gestational age, one should be guided by objective data obtained during the examination, that is, the size of the uterus and the value of the standing of its bottom, as well as the results obtained during the ultrasound examination.

Determining the term by the height of the fundus of the uterus

The size of the uterus and the height of its fundus at different stages of pregnancy

From the very beginning of pregnancy, the uterus begins to grow gradually and by each month it should have a certain size with the normal development of pregnancy:

By the end of pregnancy, the uterus reaches the size of a chicken egg;
To the size of the uterus corresponds to the size of a goose egg, which is well determined by vaginal examination;
To the uterus is determined at the level of the border of the upper edge of the pubic arch;

To the bottom of the uterus is located in the middle of the distance between the navel and the pubis (4 transverse fingers above the pubic symphysis - the articulation of the pubic bones);
By pregnancy, the bottom of the uterus is set to 2 transverse fingers below the navel;
To the bottom of the uterus is at the level of the navel;
To the bottom of the uterus is determined by 2-3 transverse fingers above the navel;
To the bottom of the uterus is set in the middle of the distance between the navel and the xiphoid process of the sternum;
To this level reaches the xiphoid process and costal arches;
Towards the bottom of the uterus, it sinks somewhat due to the deployment of the lower segment (the body is preparing for childbirth) and the lowering of the presenting part (usually the head) and is located in the middle of the distance between the navel and the xiphoid process.

This parameter should be evaluated only in conjunction with the others, since the height of the uterine fundus increases in the presence of a large fetus, multiple pregnancy, with an incorrect position of the fetus, and decreases with a small fetus, with a low standing of the presenting part of the fetus (if there is a threat of interruption). Also, the increased size of the uterus can, especially in the early stages, imitate the presence of myomatous nodes, cystic drift and other pathologies.

How to calculate the gestational age by ultrasound

Ultrasound is of great help in determining the gestational age (). In the early stages, when the embryo is not yet determined, the period is set based on the size of the fetal egg.

Indicators of the average internal diameter of the fetal egg

From the moment when the embryo begins to be determined in the fetal egg, the gestational age is set based on the size coccygeal-parietal size of the embryo/fetus(this is the maximum distance from the head end of the fetus to its coccyx). This method is more accurate than determining the term by the diameter of the fetal egg.

Estimation of gestational age based on embryo/fetus

In the second half of pregnancy, the gestational age is determined based on several measurements:

Biparietal size of the fetal head;
The circumference of the abdomen of the fetus;
The length of the femur.

The period established on the basis of an ultrasound examination correlates with the menstrual period and the data of an objective study.

Duration of pregnancy and determination of the date of delivery

The average duration of pregnancy is 280 days, which is 40 weeks. It is impossible to determine the exact date of birth for each specific pregnancy. Therefore, term delivery (that is, delivery on time) is taken to be between 37 and 42 weeks of gestation. At the same time, at 37 weeks, the child may not yet be ready for extrauterine life, but the birth will not be considered premature. And at 41-42 weeks, a baby can be born with signs of postmaturity.

How to calculate due date

The estimated due date can be determined in the following ways:

First day of last menstruation: 280 days are added to it and the date of birth is obtained, corresponding to 40 weeks of pregnancy. It’s easier to subtract 3 months from the first day of the last menstruation and add 7 days (For example, the first day was March 15, subtract 3 months - December 15 and add 7 days, we get the estimated date of birth - December 22);
By ovulation: from the first day of the expected, but not the onset of menstruation, 14 days are taken away and 273 days are added. This method is valid with regular menstruation;
By the exact date of fertilization(more often used for in vitro fertilization - 3 months are subtracted from the date or 273 days are added);
According to the gestational age established at the first visit to the antenatal clinic(more precisely when registering up to 12 weeks);
By date of first movement: in primiparous, 20 weeks are added to the date of the first stirring, in multiparous - 22;
By date of maternity leave(from 30 weeks, 10 weeks are added to this number);
According to ultrasound(the most accurate for determining the period is the first screening ultrasound at 10-14 weeks, since the fetus does not have features associated with race, gender, etc.);
According to the degree of maturity of the cervix: This method is based on the study of the cervix during vaginal examination. In this case, it is possible to determine whether the cervix is mature or not (that is, to determine its readiness for childbirth), but not to indicate the exact date.
According to the colpocytological test. This method is based on taking material from the cervix and examining it under a microscope to determine the ratio of different cells. By changes in the composition of cells, one can judge the expected date of birth.

To date, there are many special obstetric calendars that, based on the first day of the last menstruation, allow you to determine the gestational age, as well as the expected date of birth.

Nowadays, the development of the medical industry and technology makes it possible to make accurate diagnostics and predictions regarding the state of human health. This fully applies to the course of pregnancy. If earlier no one could predict the date of birth, the sex of the child, today these are quite normal phenomena. Today, even the gestational age can be determined in several ways, and even without medical participation. Let's learn about it in detail.

Why do you need to know the gestational age?

If we talk about methods for determining the duration of pregnancy, then some can be called not too accurate, but convenient and accessible to most women, while others, more accurate, require special diagnostic examinations.

All these methods for determining the term serve one goal - competent observation of the course of pregnancy, the development of the fetus. Knowing the exact number of weeks of pregnancy makes it possible to timely diagnose developmental pathologies of the unborn child (for example, Down syndrome), deviations from the norm, and accurately determine the date of future birth. When the doctor knows the gestational age, then with the help of ultrasound it is possible to compare the generally accepted indicators and characteristics of the development of the fetus with a specific pregnancy. So, let's look at ways to determine the gestational age with their advantages and disadvantages.

How to determine the gestational age by the date of conception?

Conception of a child is the fusion of an egg and a sperm, which occurs within a day or two after ovulation. Some ladies feel it for certain symptoms, others acquire special tests to identify it, and still others measure theirs for this. Therefore, for the category of women who feel the onset of ovulation and know the day of conception, it is easiest to determine the gestational age on their own.

But even if you accurately calculate the day of conception (if the sexual intercourse was once), gynecologists, for a number of reasons, put the gestation period longer by 2 weeks. Pregnant women consider this a sign of bearing a large child. Unfortunately, in the first weeks, the size of the embryos almost does not differ. Doctors simply ascertain the gestational age. According to it, the date of future birth is calculated. Therefore, knowing your gestational age by the day of conception is interesting for the pregnant woman herself, and not for her doctor.

By the way, some expectant mothers keep their own due date calendar until the end of pregnancy. Then it will be simply interesting to compare it and the medical term, to determine whose was more accurate.

The first movement of the unborn child is an important parameter in the course of pregnancy. After all, doctors, as a rule, write down the future term of childbirth, depending on the ultrasound readings in the first trimester and on the day of the baby. Women who give birth for the first time feel such movements at the twentieth week of pregnancy, and those who give birth a little earlier - at 18 weeks.

How do doctors determine the duration of pregnancy?

When a pregnant woman comes to the antenatal clinic for the first time, the gynecologist must examine her in the chair. A gynecological examination helps in identifying existing problems and determining the duration of pregnancy. Good doctors can quite accurately (up to half a week), as well as the location of the fetus (meaning its probable location outside the uterus).

You should know that a gynecological examination of a pregnant woman with a delay of 3-4 weeks, that is, for a period of 5-6 weeks, states a slightly enlarged uterus. Its size is approximately the same as that of a chicken egg. And at 8 weeks, the uterus is the size of a goose egg. Approximately in the female fist, it has the size of 10 weeks of pregnancy. Without any problems, the gynecologist determines the size of the uterus after 12-14 weeks of pregnancy. We are talking about the length of the uterus when examining a pregnant woman on the couch. In this case, the doctor uses a centimeter tape.

How to determine the gestational age by the last menstruation?

Determining the duration of pregnancy by menstruation is called the obstetric period. How is it calculated?

This is not difficult, because the ovulation period in this case is not taken into account. The duration of the menstruation itself is not important either. The doctor needs to know the date of the first day of the last menstruation of a pregnant woman. It is from this day that the doctor begins to calculate the gestational age. That is, if you went to the antenatal clinic one week after the delay and are sure that your pregnancy is 3 weeks, then the gynecologist will give you a period of 5 weeks.

How to determine the gestational age by ultrasound?

Traditionally, the first ultrasound examination for a woman is prescribed at 12-14 weeks of pregnancy. But it is problematic to establish its accuracy at this estimated period. After all, embryos in all expectant mothers develop the same way only in the first weeks after conception. Then the doctor is able to determine the period with an accuracy of one day, to clarify the location of the child in the absence of a heartbeat. And if the ultrasound shows any deviations, then a second study is prescribed in a week or ten days to accurately determine the deviations and exclude a missed pregnancy.

That is, it is possible to determine the gestational age by ultrasound only in the early stages. With two subsequent planned ultrasounds, doctors will set the gestational age in accordance with the parameters of the parts of the body of the unborn child, his head. However, we should not forget that the second half of pregnancy is a purely individual development of babies. After all, the birth of girls and boys weighing 2800 g and 4000 g is considered normal.

How long does an hCG test show pregnancy?

Recall that human chorionic gonadotropin (hCG) is one of the most important indicators of the presence of pregnancy, its normal development. HCG is a hormone that is produced in the body of a pregnant woman after the introduction of the fetal egg into the wall of the uterus, that is, after the implantation of the embryo. This happens already on the sixth or eighth day after the fertilization of the female egg. It is the presence of this hormone in the blood and urine that is the basis of pregnancy testing. Traditional tests, which are sold in pharmacies, determine the presence of this hormone with two strips.

In the first trimester of pregnancy, this hormone stimulates the production of progesterone and estrogen. These two female hormones are essential for maintaining the normal course of pregnancy.

You should know that in the first weeks, the level of human chorionic gonadotropin doubles approximately every 2-3 days. Its increase by 60 percent in two days is considered to be the norm. With increasing gestational age, the increase in hCG levels decreases. Namely, at a period of 8-9 weeks of pregnancy, the level of chorionic gonadotropin ceases to grow. On the contrary, it begins to decline at a slow pace.

By the way, during a woman's multiple pregnancy, the level of this hormone increases in accordance with the number of fetuses. That is, if there are three fetuses, then the level of hCG is three times higher than normal. It is the standard, generally accepted norms of this hormone at different stages of pregnancy that are the main determinants of this period.

It should be borne in mind that the gestational age in terms of hCG levels does not coincide with obstetric calculations. Why is this happening? The fact is that according to chorionic gonadotropin, the gestational age is stated relative to the day of conception of the child. It, in fact, displays the age of the unborn baby. But the obstetric gestational age is determined by the doctor relative to the date of the last menstruation and is not related to the term of conception of the child.

So, the above methods can accurately determine the gestational age. However, it is recommended to take into account the fact that with the most correct calculations, your baby may be born earlier than this period, and later. Therefore, the main task of the expectant mother is to do everything in her power for a healthy pregnancy and the safe birth of a daughter or son.

Especially for Elena TOLOCHIK

Each representative of the fair sex, having learned that she is in a position, seeks to calculate the exact gestational age as soon as possible. According to it, you can calculate the approximate date of birth of the long-awaited baby. Determination of the gestational age is also required by the gynecologist to track the development of the fetus, identify violations, and timely prescribe tests and examinations.

How do doctors determine the duration of pregnancy?

For women who come to a medical facility and claim to be pregnant, the gynecologist first of all asks when the last menstruation was. It is from this date that he will count. Interesting, right? Fertilization has not yet come, since it occurs during ovulation in the middle of the cycle, and obstetricians start counting from such an early date.

This method of determining the duration of pregnancy and childbirth is called " obstetric». True the period of an interesting position is about 2 weeks less than the period that the doctor tells the pregnant woman. The minimum period for determining pregnancy by this method is 2-3 weeks.

You can find out the period by the results of ultrasound. Their accuracy will be less in the later stages, because each baby develops in the mother's tummy in its own way. The doctor determines the gestational age by the size of the fetus. The following indicators are measured:

biparietal size, determined between the temporal bones (BDP);
fronto-occipital size (LZR);
head circumference (OG);
abdominal circumference (OC);
thigh length (DLB);
chest diameter (DRD), etc.

Each week is characterized by certain values of the above criteria. The gynecologist uses a special table for determining the timing of pregnancy to calculate.

The doctor can determine the period of an interesting position by the size of the uterus during a gynecological examination. For example, at the 4th week of pregnancy, the organ can be compared with a chicken egg, and at the 8th week - with a goose egg. Later, it is difficult to establish the term according to the size of the uterus.

How else do doctors determine the duration of pregnancy? For example, a method is used to determine the duration of the position along the length of the uterus. A tazomer or centimeter tape is used. As a rule, the number of weeks is equal to the length of the uterus. For example, during the measurement, it turned out that the length of the uterus is 34 cm. This means that the period is 34 weeks. To obtain reliable results, a woman is advised to empty her bladder before visiting a doctor.

How to determine the gestational age at home?

A pregnant woman can independently calculate the duration of her interesting position without the help of doctors. How to find out the gestational age at home? There are several ways:

according to the last menstruation;
by date of conception
at the first stirring of the crumbs;
using an online calculator.

1. How to determine the gestational age by the last menstruation?

The easiest way that doctors and many women find out the gestational age is by the last menstruation. How to determine the most gestational age by the last menstruation? Between the date of the beginning of menstruation and the date of the calculation, it is necessary to calculate the number of weeks. This will be the duration of the pregnancy.

By the date of the last menstruation, it is convenient to calculate the date of birth. There is a special Nagel formula. From the date of the last menstruation, 3 months are counted back and 7 days are added.

The calculation of pregnancy by the last menstruation is a fairly simple, but inaccurate method, since it is a couple of weeks longer than the true period.

2. How to determine the gestational age by the date of conception?

Recall that conception occurs approximately in the middle of the cycle after the release of a mature egg from the ovary (ovulation) during the day. The method of calculating the gestational age by the date of conception is suitable for those women who know exactly when they ovulated. The gestational age is determined by weeks. The countdown is from the date of ovulation. Average values can also be used (for example, with a 28-day cycle, ovulation approximately occurs on day 14, i.e., in the middle of the cycle). And how to determine the gestational age with an irregular cycle? In such cases, approximate values \u200b\u200bare not suitable.

The moment of release of an egg ready for fertilization can be determined using special tests, basal temperature or ultrasound results. Some women determine ovulation by how they feel (by the presence of pain in the lower abdomen, abundant discharge from the penis, increased libido). If the date of ovulation (and, accordingly, the date of conception) is unknown, then using the method of determining the gestational age by the date of conception will not work, since the results will not be accurate.

3. How to determine the gestational age by the first movement?

The baby begins to move in the tummy of the mother, whose pregnancy is the first, from the 20th week. Multiparous women begin to feel movements from the 18th week.

It is worth noting that using this method it is not always possible to find out the exact time. Some women feel the first movements much earlier than the indicated weeks, and some vice versa later. Most doctors note that the fair sex often confuses the first movements with the "work" of the intestines, because it is known that many pregnant women suffer from increased gas formation.

4. How to determine the gestational age using a calculator?

To calculate the gestational age, you can use the calculator, which is presented below. His work is based on the method of determining the period by the last menstruation, which was described above. How to determine the gestational age using an online calculator? In order to use it, you need to know the date of the beginning of the last menstruation, the average duration of the menstrual cycle and the luteal phase. The results of the calculation will be known immediately.

Summing up all of the above, I would like to note that many women are interested in the question of how to accurately determine the gestational age. However, with almost all of the above methods, it can not be calculated accurately. The only exceptions are cases when a pregnant woman knows the exact day of ovulation. Is it necessary to know the absolutely exact term of an interesting position? It is worth noting that it is not so important. Deviations of a few days or a week will not play a big role, so do not be afraid if the exact day of ovulation and conception is not known.

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