Child birth calendar by date. Calculating the date of conception - birth calculator. What is gestational age

Knowing the exact due date is important for every pregnant woman, because it is better to go to the maternity hospital in advance, on your own, and not at the emergency room. Today we will figure out why all children are born at different times and how to determine your gestational age.

The timing of birth depends on various reasons: is there a norm?

Gynecologists claim that there is no standard period for normal childbirth - there are conditional frameworks. Normal birth can occur at 37 or 44 weeks. It is generally typical for twins to be born at 36-37 weeks, and women with a long monthly cycle have every chance of giving birth after 42 weeks.

You need to understand that if a child was born normally developed at any stage, this is the norm. In case of deviations in development and health due to the timing of birth, children are divided into premature and post-term.

Babies with low weight, height, and poor development of organs and body are called premature. Their mothers carried them for less than 37 weeks - until the 260th day of pregnancy, so the babies were not able to achieve the required parameters. According to statistics, 20% of children are born premature.
Post-term babies are born after 42-44 weeks - during the period 294-308 days of pregnancy. Don’t think that if you carry your baby to term you will give birth to a giant. On the contrary, there are signs of a post-term baby: thinness, dry, wrinkled skin, weak muscles. The reason for this condition is the aging and death of the placenta, through which nutrients were supplied. Approximately 10% of mothers undergo nursing.

From all of the above it follows that it is better to give birth at 37-42 weeks. Knowing exactly when this moment should come, it is easy to navigate during premature contractions or when you are postmaturity.

Will doctors help if the due date is delayed?

Of course yes! If you notice signs of impending premature birth, you can contact a gynecologist and he will take action. If there is a threat of premature birth, bed rest and various medications are prescribed to relieve contractions and relax the uterus.

In case of postmaturity, at 40 obstetric weeks of pregnancy, the expectant mother is placed in the maternity hospital for observation. Examinations and stimulation with a drug that causes contractions speed up the process. If necessary, the doctor can open the amniotic sac, after which labor either begins or a cesarean section is performed. After the water breaks, the baby will appear no later than 12 hours later.

If the due date has nevertheless moved forward, do not despair; now both significantly premature babies and “slightly” post-term babies are being cared for. The most dangerous condition is significant postmaturity of the fetus - the baby may be born dead or with serious pathologies - every second post-term baby shows signs of suffocation, hemolytic jaundice, damage to areas of the brain caused by oxygen starvation, etc.

How to calculate due date in gynecology

The obstetric gestational age begins on the first day of your last period. It sounds a little strange, since at this time there is no child yet, but it is more convenient for doctors. In addition, pregnancy dates begin to be counted from the day of conception, which is usually considered the day of ovulation. Normally, ovulation occurs two weeks from the first day of the last menstruation.

This is where the problems with calculations begin. maybe two in a month, maybe it will move in the opposite direction. and ovulation can specifically occur due to classic stress, taking certain medications, inflammation in the reproductive organs, and other reasons. For some women, conception is delayed and can happen right on the “safe” day - just before menstruation. For others, menstruation, on the contrary, can continue even after pregnancy. In these cases, it will be more difficult to determine the timing.

Initially, the gynecologist sets the period based on a survey of the patient and data from a gynecological examination. By palpating the uterus, the doctor determines its size, which corresponds to the period of pregnancy. The estimated duration of pregnancy, for example 6-7 weeks, is recorded on the card; this indicator serves as the starting point for calculating the date of birth.

Formula for calculating due date

You can calculate the preliminary date of birth (the due date is abbreviated as PDD) using a simple formula. It is also used by obstetricians.

To calculate pregnancy, the date of the first day of the last menstruation is taken as the basis. Childbirth should take place after 40 obstetric weeks, which is. 280 days.

Formula for calculating the day of birth: From the first day of the last menstruation, subtract 3 months, add 7 days to the result.

Example: The last period began on September 5th, counting back 3 months, we get June 5th. Adding 7 days, we get the deadline for June 12th.

Online due date calculator: find out when you can give birth right now

Estimated date of conception.
Timing of important stages of pregnancy development.
Current gestational age.
Due date (date) of birth.
Zodiac sign of the newborn.

It is worth understanding that this method cannot guarantee an accurate result, because an online calculator is just a set of formulas designed for a standard situation. Therefore, it is only possible to find out the due date in this way only approximately.

How to accurately determine the due date - ultrasound of the fetus and no amateur activities!

The most reliable method for determining the due date is an ultrasound examination of the fetus, called pregnancy screening. The ultrasound specialist, based on the readings of the device, compares the size of the fetus with the standard and makes a verdict - the gestational age and the date of the PDR (preliminary date of birth). Or rather, this way you can very accurately determine the gestational age, and the date of birth will be estimated, since, as we noted above, it depends on many factors.

It is not for nothing that there is a proverb among pregnant women: “PDR was invented by the enemy,” since the coincidence of birth with the date set by the specialist does not always happen.

Causes of premature and delayed births:

Body parameters of a pregnant woman. State of health, structure and condition of the uterus.
Hormonal balance(labor begins under the influence of a hormone that stimulates uterine contractions).
Fetal parameters. Development depends on the quality of blood supply, genetic characteristics, location, etc.
Presence of dangerous infections. A number of infectious diseases can cause premature birth.
Injuries, stress and other factors.

Symptoms of delayed delivery

It’s quite easy to understand that something is wrong; the following symptoms correspond to premature birth:

Premature birth begins with aching in the abdomen, the appearance of discharge, and increased fetal activity. The stomach may not hurt - you will feel a slight “stretching” in the back. The water may break and a large amount of liquid will leak out. All these signs are 3 reasons to call an ambulance.
With true post-maturity, the belly and weight decrease. Milk may appear in the breasts instead of colostrum. And with an ultrasound, doctors will determine whether the baby is suffering from lack of nutrition or whether you simply have a prolonged pregnancy.

If you experience premature labor, there is no need to panic. If the child breathes on his own and his weight is more than 2.5 kg, then everything is in order. A little love, care and mother's milk, and he will grow up to be a great man. There are many such examples in history. For example, Napoleon Bonaparte was born two months ahead of schedule.

But if you collected all the birth packages at 37 weeks, and are already 42, then immediately go to the maternity hospital. You should not hope for a doctor’s mistake - if the due date was set on an ultrasound of the fetus, then you need to trust him.

Where to determine the date of birth in St. Petersburg?

There is a specialized one in St. Petersburg. There is a new ultrasound machine with Doppler, which also allows 4D formats. Reception is conducted by leading obstetrician-gynecologists with the highest qualification category. Prices for fetal screening are minimal, from 2 thousand rubles. - only 1000 rub. Here you can also get tested for hCG and TORCH complex.

Menstruation is delayed, and the two treasured lines are becoming more and more visible in the tests? It’s still too early to go to the gynecologist, but you really want to find out when the baby who seems to have already settled in your tummy will be born? In this case, use our service to calculate your due date.

Calculate due date online

There are several methods for calculating the expected date of birth. All of them are based on the fact that a normal pregnancy lasts on average about forty weeks, counting from the beginning of the last menstrual bleeding. The expected date of birth will fall on the day that occurs 280 days or 40 weeks after the last menstruation began.

Calculating your due date using our service is very easy, convenient and fast - it only takes a few minutes or even seconds. To do this, you need to fill in the calculator windows with the numbers corresponding to the date of the first day of your last menstruation in the following format: day, month, year.

In just a moment, the calculator will calculate and display the result on the monitor.

This service works on the principle of calculating the duration of pregnancy, which in most cases lasts for 40 obstetric weeks or 280 calendar days. You can calculate your due date yourself by adding the required number of days/weeks to the day your last period started. But with the help of this convenient calculator, calculations are made easier, faster and without errors. However, you should understand that this is only an approximate, estimated date when you can expect to give birth. The length of pregnancy is influenced by a large number of factors, so it can last for different periods of time in different women.

Calculate due date based on date of conception

If you reliably know the day when fertilization occurred, then calculating the date of birth based on the date of conception will be even more reliable. To find out when the baby will be born, you need to add 280 days to the day on which the cherished sexual intercourse took place.

It should be understood that the date of sexual intercourse (even if you are almost one hundred percent sure of its authenticity and even if this month you had only a single case of sexual intercourse) is not always the date of conception of the child. The thing is that ovulation (the release of an egg ready for fertilization) can occur a day or two or even more after sex, but sperm that entered the vagina earlier can wait until this moment to merge with the egg and form a new life. Thus, the calculations may be off by several days. But still, the date of conception can be determined approximately.

You can also calculate the expected date of birth based on the day of ovulation. If you keep an appropriate schedule, the calculations will be quite accurate. But you can roughly calculate that very day, even without knowing the exact date of ovulation. It is believed that the egg matures approximately in the middle of the cycle. With a 28-day menstrual cycle, this moment occurs on days 12-15. By adding 280 days to the day of expected ovulation, you can calculate the date of birth.

Well, having received the result, proceed to pleasant chores and do not forget to visit the antenatal clinic on time, where you will be monitored for the next nine months.

Researchers from the Oregon Center for Genetics and Perinatal Medicine (USA) analyzed several thousand birth histories and came to the conclusion that in the vast majority of cases (95%) the date of birth does not coincide with the one they tried to determine in advance

How to determine the due date? Sometimes you want to know exactly when the baby will be born just out of curiosity, and sometimes for some practical reasons: state exams at the institute, moving to a new apartment, and who knows what else. In a word, almost all mothers want to know more precisely when the baby will come into this world. However, it is not possible to calculate this date absolutely accurately, down to the day. And that's why.

Let's assume that the mother knows exactly when the fateful sexual contact took place, which gave birth to the baby, but sexual contact and the date of fertilization are far from the same thing. After all, it is known that sperm that enter the female genital tract retain the ability to fertilize an egg from several hours to several days.

If they try to determine the beginning of pregnancy by the date of ovulation, then everything is not so simple here either, because ovulation can occur between the eighth and sixteenth day of the cycle. And this depends on the duration of the cycle, and on many external reasons, such as fatigue, anxiety, colds.

We take into account that pregnancy can occur a couple of days after ovulation, when the egg and sperm are still viable and ready for conception, that is, right up to the eighteenth day of the menstrual cycle, and if we take into account the viability of individual sperm that have entered the female genital tract, we can safely add a couple more days. Thus, it turns out that pregnancy can quite realistically occur before the twentieth, or even the twenty-first day of the cycle.

And if the menstrual cycle is short, then everything becomes even more confusing. Suppose the menstrual cycle is 21 days, but the periods are long - lasting a week.

Then ovulation occurs almost immediately after menstruation, and even if unprotected sexual intercourse occurred during menstruation, then, given the ability of sperm to fertilize within several days, pregnancy is quite likely even after such sexual intercourse. A short cycle, ovulation on the eighth–ninth day, sperm viability - this means pregnancy even with intercourse during menstruation.

So you can remember the date of sexual intercourse absolutely accurately, but it is not at all a fact that pregnancy occurred right then, and not slightly later.

What else can influence the date of birth, and at the same time complicate the calculations? Traditionally, a normal pregnancy is considered to last 40 weeks. But this is not always the case - the fact is that the pregnancy is considered full-term by the 38th week, therefore normal labor can begin at any time after this period.

One more point: if twins are to be born, that is, the pregnancy is considered multiple, then in the vast majority of cases labor begins a week or two earlier.

Don’t forget about a young mother: for example, a mother’s hypertension can delay the due date in the same way as diabetes. Any chronic and acute health conditions, emotional background, fatigue - absolutely everything can affect the timing of childbirth.

There are a lot of reasons that can affect the due date, let’s add here the practical impossibility of accurately determining the date of conception - so it turns out that the date of birth can be guessed or not, but it is practically impossible to calculate it with any certainty.

The main thing is to treat this with understanding - the baby will come into this world only when he is completely ready to face sunrises and sunsets, snow and rain, sun and rainbows.

However, be that as it may, the approximate date of birth can be determined (but only approximate!). It must be said that gynecologists suggest determining not the exact date of birth, since this is still very problematic, but the week when the birth should occur.

Let's ask the moon

A very popular miscalculation option is when ten lunar months (280 calendar days) are added to the beginning of the last menstruation - thus getting the expected day of birth. There is another option: from the beginning of the last menstruation, three months are counted and seven days are added (Nägel method) and the approximate due date is obtained.

Why are these calculation methods inaccurate? Yes, because the menstrual cycle is not always 28 days, it can be noticeably shorter or significantly longer, in addition, the menstrual cycle is not always regular - and then it is generally impossible to determine the date of ovulation.

But if the mother absolutely knows her cycle, which, besides everything else, is always stable, then you can try to calculate the date of the expected birth in one more way.

The day of conception should be determined by subtracting 14–16 days from the first day of menstruation that never came. And if the day of conception is known, then, based on the duration of pregnancy of 10 lunar months, the day of birth can be determined. But everything, again, is very approximate.

Let's move!

You can try to determine when the baby will be born by noticing when it first began to move in mommy's tummy. The day of the first fetal movement is a very significant date.

If a young woman is going to become a mother for the first time, then twenty weeks should be added to the day when the baby first moved, and if the mother is not going to give birth to her first child, then twenty-two weeks should be added.

The fact is that the baby’s movements are perceived very subjectively: women who have already given birth can feel the baby’s movement much earlier, even before the eighteenth week of pregnancy, and a nulliparous mother can confuse the baby’s movements even with intestinal peristalsis - everything is extremely individual. This is where the inaccuracy of this method of determining the due date comes from.

Consult a consultation

“By first appearance at the antenatal clinic” is the name of the next method for determining the time of birth. The sooner a woman contacts an antenatal clinic about pregnancy, the more accurately the gestational age and, accordingly, the due date will be determined. It is generally accepted that the most accurate prognosis can be obtained if a woman consults a doctor before twelve weeks of pregnancy.

In addition, the doctor can determine the gestational age, respectively, and the date of birth, based on some completely objective indicators: the size of the uterus, the volume of the abdomen, the height of the uterine fundus, the length of the fetus and the size of the head. At four weeks of pregnancy, the size of the uterus is approximately the size of a chicken egg, at eight weeks it reaches the size of a goose egg, and at 12 weeks of pregnancy, the uterus is approximately equal in size to the head of a newborn.

The abdomen becomes noticeable (the so-called protrusion of the abdominal wall) at the end of the twentieth week of pregnancy (the end of the fifth obstetric month).

The gestational age can then be determined by how the upper edge of the uterus is positioned.

Ultrasound and due date

Ultrasound examination is one of the most modern and most reliable ways to determine when a baby will be born.

It’s interesting, but the most accurate way to determine the date of future birth is to use ultrasound data obtained up to three obstetric months (12 weeks). At this stage, the fetus develops approximately the same for everyone, and the gestational age can be determined after measuring the fertilized egg and its internal diameter.

Later, in the second and third trimesters, they try to determine the exact gestational age by studying ultrasound data on the circumference of the fetal head, the diameter of the baby’s chest and tummy. But the most reliable information is obtained after measuring the circumference of the baby’s head.

It would seem that the closer to the time, the more accurately you can determine the due date. But no! It is believed that in the later stages of pregnancy it is much easier to make a mistake during an ultrasound, and no wonder, because each child develops in its own way, and by the end of pregnancy, children are completely different: a healthy child can be born weighing 2.5 kg, or weighing 4 .5 kg. So it’s not for nothing that ultrasound data are the most accurate at the very beginning of pregnancy, when the cell has just begun to divide, and the individual characteristics of the baby are not yet particularly pronounced.

There is no reliable method

But no matter how hard a young mother tries to determine the time of birth and find the most reliable method, only one thing can be said with confidence - there is no completely reliable method for determining the time of birth.

It is possible to speak with any certainty about the timing of birth only if the information obtained from all methods does not contradict each other, but only complements each other. Although no matter how accurately the timing is predicted, labor will still begin only when the baby decides that it is time for him to take a closer look around. The main thing is that the birth should be on time, that is, on time, and this is the period from the 38th to The 42nd week of pregnancy, and the exact day of birth can only be guessed by chance, and the day named by doctors is a very approximate date.

It is clear that the young mother is very worried, and if contractions do not start at the “calculated” time, this can cause severe stress.

But every pregnant woman should understand well that it is impossible to accurately determine the time of birth, that any doctor, based on the results of any research, can only give an approximate (so-called estimated) date, and the difference with the actual birth can reach up to two weeks (either one or two weeks). other side). So a young mother must trust herself, her feelings, listen to the child inside herself - he knows exactly when he should be born.

Stanford University follows the following calculation formula:

Set the first day of your last menstrual period.
Count back three calendar months
Add a year and seven days to this date.

For example, your first day of your last menstrual period was September 9, 2019. We count back three months and get June 9, 2019. We add a year and seven days, we get June 16, 2019, traffic rules - the expected date of birth.

The site team understands how important it is for expectant mothers to be on guard, so they offer a new service - an interactive pregnancy calculator, designed specifically for you.

Using our calculator, you can accurately calculate your due date and all the main points of your pregnancy. The calculation will take just a few seconds, the page will refresh, and you will receive your estimated due date. Now you will know exactly when your baby will be able to move his fingers, respond to your touch, and hear your voice.

If it seems to you that you became pregnant earlier or later than your menstruation, then after a routine ultrasound you can once again calculate the gestational age, based on a number of medical indicators. Thanks to our service, you will know the answers to many questions regarding your gestational age and expected due date.

Benefits of use
pregnancy calculator:

Every woman has many questions when she becomes pregnant. When will your belly start growing? When will the baby start moving? When do you need to register at the antenatal clinic and when can you go on maternity leave? When can we expect the baby to be born? All these questions can be answered on our website. We described week by week all the changes in the body of the mother and child, indicated all significant events;

Using the pregnancy calculator, you can find out the exact timing of each trimester, significant dates (conception, childbirth, prenatal leave);

At the appointment, the doctor will definitely ask about changes in the woman’s condition. Using a calculator, it is very convenient to see what to pay attention to, when certain symptoms should appear;

The obstetrician-gynecologist will definitely draw up an examination plan, tell you which week you need to take certain tests, do an ultrasound and other instrumental studies. The electronic pregnancy calendar is a convenient reminder of exactly when and why you need to go to a consultation. We have tried to explain why each analysis is performed and how to evaluate its results.

An online pregnancy calculator is a convenient service that helps a woman have a clear idea of the course of pregnancy and the sequence of events.

An approximate calculation based on the average cycle length and the beginning of ovulation - plus 14 days to the beginning of the last menstruation.
Full 40 weeks.

In medicine, there is a term applied to the timing of pregnancy - the expected date of birth (EDD). When expectant mothers come for their first pregnancy examination at the antenatal clinic and register, the doctor makes calculations and tells the woman the approximate day of birth.

It focuses on the date of the last menstruation, which every woman needs to know. The gynecologist will definitely ask the patient whether they started and how long they lasted.

If the expectant mother has a regular menstrual cycle (once every 28 days), the doctor adds 14 days to the start of menstruation and gets the approximate date of conception. The maturation and release of the female egg, that is, ovulation, occurs precisely at this time.

Women need to mark the exact dates of the start of menstruation on a desktop or small calendar all the time; this can be useful both during pregnancy and any time you visit a gynecologist for advice.

Sperm can fertilize an egg immediately on the day of ovulation, or maybe after 1-3 days. Therefore, today only a doctor performing an ultrasound can tell the exact date of conception.

If the pregnancy lasts no more than 12 weeks, the doctor can accurately indicate the date of conception. At later dates it is more difficult to do this. Therefore, it is important for the expectant mother to undergo an ultrasound in the first weeks of pregnancy.

After the ultrasound examination, the doctor will add 28 weeks or 266 days to the figure in the colleague’s conclusion, plus another 14 days that have passed from the last date of the onset of menstruation to ovulation, and will receive a control figure. It is communicated to the pregnant woman as the date of the long-awaited event.

The birth of a baby is always a joy, but this joy appears under different circumstances. The baby may be born before the due date specified by the doctor, or it may linger in the mother’s belly for various reasons.

Women who have suffered severe infections or suffer from endocrine diseases are less likely to carry their fetus to term.

A pregnancy between 38 and 42 weeks is considered full-term. If a woman walks for more than 42 weeks, then this is a post-term pregnancy. The timing can be influenced by the mother’s health status, her diet and environment, as well as the characteristics of the child’s intrauterine development.

The well-known Naegele formula is also used to calculate the date of birth. According to it, you need to add 9 months to the last date of the start of menstruation and then add another 7 days.

Based on the day of the first fetal movement, you can also approximately calculate the date of birth of the child. You need to add 20 weeks to it if the pregnancy is the first and 18 weeks if the second. The error will be about 2 weeks, which is quite a lot compared to the date given after the ultrasound, for example.

So the expectant mother can calculate the date of birth on her own, but it will still be estimated, as obstetricians and gynecologists say. Doctors advise you to worry more not about the exact day when the baby will be born, but about successfully carrying the child to term.

A healthy, optimistic mother will give birth well both a day earlier and a few days later. The main thing is to have time to prepare for the desired event on time, and even the approximate date of birth will help with this.