Calculate pregnancy by week and month. Terms of pregnancy: obstetric and embryonic - how to determine and not get confused in terms
Pregnancy calculators
The calculator calculates the duration of your pregnancy by the last months. 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, circles 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 exercise. But modern women live at a great time - they are not at all obliged to keep such a calendar and engage in tedious arithmetic, unless, of course, they are so sentimental that they decided to keep their weekly notes as a memory of the wonderful time of gestation. You can safely entrust the program with taking care of calculating the gestational age. Indeed, 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 (hinting at our calculator).
What do you need to calculate the gestational age?
In order to calculate the gestational age right now, you just need to remember the date when the last menstruation began and enter it in the appropriate fields of the form. 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 that with an ultrasound examination of the fetus, you will be faced with the fact that the gestational age known to you can be calculated differently - by the weeks of the fetus's life, that is, from the day of conception. You can even find an entry on the ultrasound study results sheet, which will indicate both terms. In order not to be embarrassed by such contradictions, feel free to ask the doctors what kind of gestational age are we talking about, real or obstetric?
It is very important to emphasize that even if you know for sure the date of conception of the baby, in order to calculate the gestational age using a calculator, you need to use the date of the beginning of the last menstrual period. 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 my period was. What to do?
Sometimes it happens that a woman does not know when she had her last period, for example, does not remember, does not follow the regularity of the cycle, or has just stopped taking contraceptives. If you have no idea what your pregnancy period is, you can calculate it at. The data obtained in the early stages (up to 12 weeks), when the rate of development of the ovum is still very high and changes are noticeable literally every day, have the greatest reliability. The size of the ovum alone, without taking into account the proportions of the fetus, will tell the doctor a lot. At a later date, 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 ovum and is present in the body only during pregnancy (by the way, the well-known instant pregnancy test is based on its determination in the urine). The content and with a healthy pregnancy clearly correlates with the timing. It is worth noting that this is far from a routine method that requires a lot of time and money, and it is used mainly for medical reasons.
It is impossible not to mention that it is within the competence of the obstetrician to find out the gestational age, calculate and assume the probable age of the fetus 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 for the successful monitoring of the health of the expectant mother and fetus.
Questions to the article
On the ultrasound scan on 06/30/2017, the doctor said nothing is visible, only there is a cyst ...
Looked at the test, but I got a negative result. but so ...
The lower abdomen hurts periodically, it swells, the stomach hurts, what can it do ...
Please, from what week can you feel the fetal movement? ...
The size of the ovum corresponds to 3-4 weeks, for hCG at 2.02 4539, at 4.02 ...
Pregnancy ... but it's too early to do the test and there is no delay, but I already ...
The result is hCG 20.9 mlu / ml. what is my pregnancy period? the last ...
Please. The first day of the last menstruation is 04/20/2016. (conception by ...
Accordingly, the period should be 8 weeks, but they put on an ultrasound 4-5 ...
Highlights (brownish), what could it mean? ...
Why should a pregnant woman and a doctor know what stage of pregnancy? Firstly, to determine the due date, secondly, in order to adequately monitor the development of the baby, correcting possible developmental lag in time, and thirdly, to determine the period of care for maternity leave.
I want to make a reservation right away that they distinguish between obstetric and true terms of pregnancy. Obstetricians begin to count the gestational age from 1 day of the last menstrual period. This is quite justified, because from this moment the egg cell begins to ripen, which will be fertilized by the sperm in the future, formed and implanted in the zygote's uterus, the ovum with the embryo and then the fetus will begin to develop (after 12 weeks of pregnancy). The duration of pregnancy from the first day of the last menstrual period to childbirth is about 10 lunar months or 280 days or 40 weeks. However, each fetus has its own term of intrauterine development - from 37 to 42 weeks. It depends on many factors, but primarily due to genetics. It is necessary to inquire at what stage of pregnancy the patient herself, the father of the child, was born, how long the pregnancy was carried out by the maternal relative.
The true gestational age lags behind the obstetric one by two weeks - it is counted from the day of ovulation and conception. Thus, to determine the obstetric gestational age, two weeks must be added to the true one.
How to find out the duration of pregnancy by ovulation and date of conception
Ovulation is the very period of the menstrual cycle when conception can occur. During ovulation, a mature egg comes out of a woman's ovary into the fallopian tube and "waits" for sperm there. Unprotected intercourse at such a time in a more or less healthy woman and man will most likely lead to pregnancy. By the date of ovulation, the gestational age is determined.
A woman ovulates around the middle of her menstrual cycle (but not every month). If your menstrual cycle is 28 days, then ovulation will occur somewhere on the 14th day, with a 35-day menstrual cycle - on the 17-18th day of the cycle. The exact gestational age should be counted from the day of ovulation.
Ovulation can also be determined at home, using special tests sold in almost any pharmacy, or by regularly measuring basal temperature (temperature in the rectum). Throughout the first half of the cycle, it will stay at approximately the same level - below 37 degrees. The day before ovulation will decrease slightly. And on the day of ovulation and on all subsequent days, you will keep at the level of 37-37.2 degrees. Thus, you can calculate the gestational age () if it began in the menstrual cycle when you determined your ovulation.
There are women who can determine their ovulation without any tests and temperature measurements, just by subjective sensations - pain in the lower abdomen, increased libido, an increase in the amount of vaginal discharge. It is not difficult for such sensitive women to determine the gestational age on their own.
The most accurate way to determine the gestational age by the date of ovulation is an ultrasound scan. This is the only way to accurately see ovulation. Only now it is problematic for a week, or even longer, to go to an ultrasound scan every day. And financially, such "pleasure" will not be available to every woman. Trying to determine ovulation in oneself only so that later it is possible to accurately calculate the gestational age is inappropriate. There are simpler ways to calculate the gestational age already, in fact, after the onset of an interesting situation.
From the first date of the last menstruation, the number of days (weeks) is counted at the time of the examination of the pregnant woman. To determine the day of birth, 280 days (10 lunar months) are added to the first day of the last menstruation, or the Negele formula is used: 3 months are taken from the date of the beginning of the last menstruation and 7 days are added. This method cannot be used on women with irregular menstrual periods.
Determination of the gestational age by gynecological examination.
If you come for an examination to a gynecologist in the first weeks of pregnancy (3-4 weeks), then it will not be difficult for the doctor to accurately determine the gestational age. In this case, it is made based on the size of the uterus. For example, at 4 weeks of gestation, the size of the uterus can be compared with a chicken egg, at 8 weeks - with a goose egg. An experienced gynecologist is able to determine the gestational age through a vaginal examination with an accuracy of one day. The gestational age later than 8-12 weeks will be difficult to determine precisely based on the size of the uterus. Since, starting from the second trimester of pregnancy, in women at the same stage of pregnancy, the size of the uterus may differ.
Determination of the duration of pregnancy by ultrasound.
Of course, here, as with the previous method, much depends on the qualifications of the doctor who interprets the results. Ultrasound data obtained before the 12th week of pregnancy are considered the most correct for determining the date of the alleged birth. At this time, the determination of the gestational age is based on the measurement of the ovum, its average inner diameter.
In the second and third trimesters, the gestational age is established on the basis of determining such parameters as the circumference of the fetal head, the average diameter of the chest and abdomen of the fetus, and the circumference of the fetal tummy. The information obtained when measuring the circumference of the baby's head is considered the most reliable.
However, in general, it is believed that in late pregnancy, the error in determining the term using ultrasound increases. This is understandable: after all, each child develops individually, and at the end of pregnancy, the size of the fetus, which the doctor is guided by in his calculations, can vary significantly depending on the characteristics of a particular child.
With all the variety of methods for determining the due date of the upcoming birth, there is no one "completely accurate", as we have already said, does not exist. Therefore, we can say that a more or less accurate determination of the term of the upcoming birth is possible if all the data obtained are not contradictory, but complement and reinforce each other.
Although even in this case, the date of birth can be shifted by one to two weeks in one direction or the other due to the fact that urgent labor (that is, delivery on time) can occur in the period from 38 to 42 weeks of pregnancy.
Determination of the gestational age by the first stir.
Primiparous women begin to feel the first movements of the baby at a gestational age of 20 weeks. Multiparous a little earlier - at 18 weeks. Gynecologists recommend that a woman remember the date of the first movement and must enter it into the dispensary card of a pregnant woman. When setting the term of pregnancy and childbirth, this is of great importance. For example, in order to determine the date of birth, it is necessary to add 20 weeks (or 4.5 months) to the date of the first stirring; for multiparous, it is necessary to add 18 weeks or 5 months.
But this method of determining the gestational age is not always correct. There are women who, even in their first pregnancy, feel the baby's movements much earlier than the due date at 20 weeks, at 17 weeks, or even earlier. Especially often, such early movements are observed in thin women. There are women who feel the first movements 2 weeks later than the due date.
Doctors have their own opinion about such early perturbations and staging on their basis the gestational age. Most experts believe that women, ahead of time, do not feel the baby's movements at all, but the "work" of the intestines. After all, as you know, most pregnant women suffer from increased gas production ...
Determination of gestational age by measuring the length of the uterus and fetus.
You can calculate the gestational age in a more complex way. Such a calculation can only be made by a gynecologist. You are unlikely to succeed on your own. So, in order to measure the length of the uterus, the woman lies down on the couch and straightens her legs. Beforehand, it is imperative to empty the bladder, otherwise errors in determining the correct gestational age are possible. The length of the uterus is measured with a tape measure or pelvimeter. Usually the length of the uterus is equal to the number of weeks. For example, the length of the uterus is 36 cm, which means that the gestational age is also 36 weeks.
The long-awaited pregnancy has come, and you really want to know when will you see your baby? To calculate the gestational age and the expected day of birth, you only need to know one date: the day of the start of the last menstrual period. It is according to her that the gynecologist will calculate the gestational age, when you come to the clinic to register.
Calculate pregnancy term online
Only a few women can accurately name the date of conception of a child in order to accurately calculate the real term of pregnancy. And even in this case, the birth of a new life may occur on another day, when the future parents do not know about it. At the same time, almost every woman remembers the date of the last menstruation, which is why it is her obstetricians who take it as a starting point. Theoretically, ovulation - the period when the egg is ready for fertilization - occurs in the middle of the menstrual cycle. Therefore, there is a difference of approximately two weeks between the actual age of the fetus and the obstetric gestational age (which begins on the first day of the last menstruation).
So, in order to calculate your pregnancy period online, you need to remember when your last period began. Two weeks are added to this day: it is during this period that the egg fully matures - and fertilization can occur. Then you can calculate the estimated date of birth in two ways: first, when forty weeks are added to the date of the first day of the last menstruation. The second - from the day when conception could occur, three months are subtracted and seven days are added to it.
But if you don't like messing around with calculations, an interactive pregnancy calculator will do it for you. Enter your details (the date of the first day of the last menstruation) - and within a second you will receive the result of pregnancy in weeks and days.
Calculate pregnancy by date of conception
This calculator can also be used to calculate the gestational age by the day of conception if you are confident in the accuracy of this date. In this case, you will find out the actual (gestational) gestational age, which will correspond to the age of the fetus. The obstetric period that the doctor will set you on the first day of your last menstrual period will differ from it by about two weeks (that is, it will be more gestational).
Using our calculator to calculate the pregnancy period by week, you can also find out the approximate due date and start preparing for them in advance: find a comfortable maternity hospital and a good doctor, study breathing techniques during childbirth, choose a comfortable posture for childbirth, think about partner childbirth, arrange nursery and stock up on everything you need to care for the newborn.
Most of the fair sex is looking forward to two cherished stripes. And so, as soon as they find out that everything worked out, they have a question: from what day do they count the pregnancy? Unfortunately, it is almost impossible to determine with an accuracy of the day. The only exception is constant monitoring of ovulation. But it is carried out only during infertility. But there are other ways, the help of which is more or less correct calculation of the gestational age. These are medical research, calendar methods, gynecological examinations ... Let's figure out what the existing types of determining the period of an interesting position of a woman are.
We consider carefully
Some people believe that the stork's waiting time is the amount of time that has elapsed since conception. This point of view holds because it is quite correct. Only in this case the embryonic term is meant. It usually lasts 38 weeks. But the toddler may be asked to enter this world a little earlier or a little later.
Modern medicine takes into account not the embryonic period of pregnancy, but the obstetric one. Its peculiarity is that the first day of the last menstruation is used for counting. This will be the first day of pregnancy. When a woman registers, the doctor enters this date into the exchange card and relies on it when calculating the term.
It is known that ovulation occurs approximately in the middle of the cycle. Because of this, it becomes clear from what day doctors consider pregnancy. And therefore, the difference between obstetric and embryonic stages of pregnancy is exactly two weeks (the first period is longer than the second). In the first seven days, the egg begins its maturation and preparation for fertilization.
Oh, those forty weeks!
Pregnancy usually lasts 40 obstetric weeks. But the appearance of a baby at a period from 38 to 42 weeks is also considered the norm. Formally, pregnancy can be considered premature or postterm, but in reality, childbirth occurs at the time set by nature - just in time. Here, of course, the question arises: from what day is pregnancy considered? And this interest is understandable, because the discrepancy in the dates lies in the fact that the calculated obstetric term is very average. It can coincide with embryonic only when the baby is conceived in the middle of the 28-day cycle. And then on condition that the cycle before pregnancy was regular.
In addition to the usual calculations using the calendar, the doctor can set a deadline, taking into account the data of ultrasound diagnostics. This will be possible only if the future toddler develops according to all stages of pregnancy.
If the expectant mother believes that conception did not occur in the middle of the cycle, as is the case in most cases, but shortly before its end or at the beginning, she must inform her gynecologist about this. Then the doctor will correct his calculations in order to determine the PDD (preliminary date of birth) as accurately as possible.
Calendar method
This method is designed to control every intercourse. If the union of bodies does not happen so often, then the woman will definitely understand on what day fertilization took place. Some potential mothers have taught themselves to measure basal temperature. Once they have learned how to use the schedule correctly, they should inform their doctor about the day they have taken. Based on this information, the doctor will set an approximate date with an error of two weeks.
From what day is pregnancy considered in this case? The inaccuracy is based on the fact that people in white coats take into account only the obstetric term, the peculiarity of which is its dependence on the first day of the last menstruation. This is a very precise technique, and the due date is set within a week. And you can calculate using a simple formula, known for certain to many: the actual fertilization day + 280 days. Or subtract three months from the day of conception and add seven days. If a potential mother knows the exact day of her ovulation, then only 264 days need to be added to the day of conception. This will also be the correct result.
Such a familiar and promising ultrasound
For many years, ultrasound radiation has been used in medicine to control the development of the fetus. After all, every expectant mother is very worried about how to count pregnancy correctly, and with the help of an ultrasound scan, you can calculate both the approximate time of conception and childbirth. To get a more accurate result, doctors recommend examining a pregnant woman in the first 8 weeks. It is at this stage that each fruit develops in exactly the same way. The term is determined by its size.
But further development of each future toddler takes place strictly individually. Body parts and organs can develop more slowly or faster than the patterns suggest. A simple conclusion can be drawn from this: the shorter the gestation period, the better and more effective the expert response will be. The doctor checks the result with the data in the table and verifies the week of pregnancy. If an ultrasound scan establishes a delay in fetal development, then a diagnosis will be made about this. And the only thing that can at least slightly accelerate the development of the little one is that the expectant mother will be very attentive to her health.
At a gynecologist's appointment
Some of the women are mistaken when they come to see the gynecologist on the very first day of the delay, hoping that only he is able to answer whether pregnancy has come or not, and in case of a positive answer, determine the first day of pregnancy. But at this moment it is impossible to determine it. Yes, the uterus will be slightly enlarged, but this may be due to future menstruation. And its increase associated with the beginning of a new life will occur only after the second or third week of delay. The size of the uterus at this stage will be the size of a hen's egg. The peculiarity of examinations by a gynecologist is the same as that of an ultrasound scan: the shorter the period, the more accurately the exact date of conception will be determined.
Pregnancy with IVF
The number of women who decide on artificial insemination is increasing every day. This method assumes that the egg will be combined with the sperm, after which specialists will monitor them for several days. And here a woman who undergoes such a procedure has the right to inquire from what day a pregnancy should be considered with IVF. And everything is simpler than it might seem: the embryo is planted no earlier than after three to five days. This is when pregnancy begins.
If a woman has a short cycle, the obstetric period is set from the day of the last menstruation. And if it is long, then there will be some peculiarities. The potential mother will start taking medications that block the activity of the ovaries (their stimulation will begin later). Therefore, if you count from the last menstruation, then in real life the development of the fetus will be 3-4 weeks, and the calculated period is 7-8 weeks. Therefore, there is no problem to understand from what day the pregnancy is considered - from conception or implantation. Gynecologists are counting from the day the embryo is implanted into a woman's body.
Getting ready to give birth to a healthy toddler
Instead of arguing with the doctor about the situation from what day people in white coats consider pregnancy, it is better for the expectant mother to direct all her attention and care to the new life that is growing in her. Indeed, for the development of the baby, it is important not only the physical health of the mother, but also the psychological one. A woman should try to experience more positive emotions, breathe fresh air more often, eat more plant foods, eat a lot of seasonal vegetables and fruits.
Being pregnant is one of the most joyful moments in every woman's life. She must try not to spoil her joy of waiting for the baby. A mother-to-be should simply enjoy her current position, rest more and remember that a child is happy only when his mother is happy.
Pregnancy is one of the most exciting and at the same time crucial periods in the life of every woman, and therefore it is not at all surprising that each of us wants to know the date of birth as soon as possible. However, this issue often causes many controversies and controversies. Future mothers "torture" doctors with their questions, because they want to prepare for an important event, but they only shrug their shoulders, because they are not able to accurately determine the date of birth of a long-awaited baby.
In order to Calculate the due date, press the button "find out the due date".
Today: 18.03.2019
Date of the first day of the last period:
Conception most likely happened (+ -2 days):
Estimated due date:
Left before delivery:
Estimated due date (PDD) is calculated in several ways, each of which is indicative. That is, if, according to estimates, the baby should be born on January 1, then it is not a fact that this will happen with 100% accuracy on this very day. Very often there are deviations from the expected date in one direction or another. And labor can start either 2 weeks earlier or later. I bring to your attention a fairly simple, but very effective way to find out the probable date of birth of a child, which has been successfully used by many doctors in clinics for quite some time now.
Calculation based on the last day of your period
So to yourself calculate the gestational age and on it to determine the expected day of birth, you need to remember the date of the beginning of the last menstruation. It is on its basis that all calculations are made. From this date, you must subtract 3 months and add another 7 days to the result. The resulting number will be the estimated date of birth of your long-awaited baby.For example, the date of your last period is April 22nd. This means that 3 months must be subtracted from this date. We subtract and get - January 22. We add another 7 days to this figure and we get January 29 - this day will be the estimated date of birth.
It is worth noting that this method of calculation is best for women with a regular menstrual cycle that lasts 28 days.
4 alternative ways to calculate due date
- 1. You can find out the due date of birth, with a fairly high accuracy, by visiting the gynecologist's office. The doctor will not prescribe any tests for this, he will simply measure the size of the uterus, which will be enlarged in accordance with the age of the fetus. However, this method of calculating the date of birth of a baby is effective only in the first trimester of pregnancy. In the later lines (in the 2nd and 3rd trimester) in each woman, the increase in the size of the uterus occurs with varying intensity, depending on the individual characteristics of the organism.
- 2. You can calculate the date of birth by ovulation, which is the most favorable period in which conception is most likely to occur. On such days, a woman usually experiences an increased sex drive. In addition, her secretions (cervical fluid) become stickier and thicker, the basal body temperature rises by several tenths of a degree, the cervix rises, and the mammary glands become thickened and painful.
In the same way, you can perform calculations based on the date of conception. However, you should be aware that this period does not always coincide with the day on which the sexual intercourse took place. Fertilization of the egg, as a rule, occurs only on the third day.
- 3. Hardware calculation using ultrasonic waves can also be attributed to the most effective methods that allow you to determine the due date with an accuracy of 1-3 days. The most correct calculations will be if an ultrasound scan is done during the period of 11-14 weeks of pregnancy.
- 4. To declassify the secret of your baby's date of birth will help his first movement, which usually occurs at the 20th week (in primiparous) and at the 18th - during the second and subsequent pregnancies. In ancient times, when there was no ultrasound, this method of calculating the due date was almost the only one.
The effectiveness of hardware methods in calculating the term of labor
Examination of the fetus in the third trimester on an ultrasound machine allows you to determine the date of pregnancy with high accuracy, and therefore the expected due date. The fact is that only with the help of ultrasound diagnostics, the doctor can observe the state of the placenta, the position of the baby's head in relation to the entrance to the small pelvis, the level of cervical opening, signs of fetal maturity, as well as many other important factors. All these parameters are decisive in determining the readiness of the future baby and his mother for childbirth.Is deviation from the established date the norm?
As mentioned above, all estimates of the expected due date are nothing more than an approximate guideline, which should not be relied heavily on. According to statistics, only 17% of women give birth on the appointed day, while the remaining 83% - either earlier or later. Thus, we can conclude that no specialist, no matter how smart and qualified he is, is able to predict with high accuracy the date of onset of labor.Normally, childbirth can occur between 38 and 42 weeks. pregnancy. The birth of a child will not be premature or late, but normal and physiological. Sometimes, for some reason, labor can begin prematurely. This happens due to abnormalities in the development of the fetus, stressful situations, various pathological processes occurring in the mother's body, hereditary factors, etc.
Often there is a prolongation of pregnancy due to the fact that there were any complications in the first trimester. In addition, maternal heredity should be considered. If your mother and grandmother gave birth much later than the due date, then most likely the same will happen to you. Therefore, it is very important to realize that calculating the due date is a very difficult, conditional and individual issue for each expectant mother.