Calculate when the baby is born according to the last menstruation. Calculate Due Date with Calculator

27.08.2019

Almost every pregnant woman is very interested in when her baby will be born. There is no exact method for determining the day of birth. But there are quite a lot of methods that allow you to calculate the expected date of birth (EDP). How to use these methods, and which one is the most accurate? More on this later!

Determination of the date of birth by the date of conception

By the date of conception, you can set the approximate birthday of the baby. It is known that the conception of a child can occur only during the period of ovulation, i.e. at the time when the finished egg leaves the follicle and goes to meet the spermatozoa.

As a rule, ovulation occurs on the 14th day of the menstrual cycle. Under the menstrual cycle should be understood as a period of time from 1 day of menstruation to 1 day of the next. For each woman, the duration of this cycle is individual. On average, it is 27-29 days, but can stretch up to 35 days or even more.

Women who carefully monitor their menstrual cycle and plan pregnancy are usually able to determine their day of ovulation.

Knowing the date of ovulation, you need to add 280 days to it(namely, how long the average pregnancy lasts for women). You can find out the expected date of birth of a child using this method only if there is a constant menstrual cycle.

At the same time, you need to understand that the day of sexual intercourse is far from always the day of conception, because. the life span of spermatozoa can reach 3 days.

Calculation of due date based on last menstrual period

The approximate birthday of the baby can be calculated from the last menstruation. You need to know the day it started. To determine the approximate date of birth of a child count forward from the first day of the last period 280 days(average duration of pregnancy).

According to statistics, no more than 5% of children are born on the “settlement” day. About 85% of babies are born with a deviation of 5-7 days from the calculated due date, and the remaining babies are "hurry" or "late" for another week. According to medical standards, the normal duration of pregnancy is 38-42 weeks, and not strictly 40 weeks, as many people mistakenly believe for some reason.

At the same time, a variety of factors can influence the duration of pregnancy, including the individual rate of development of the child and the duration of the menstrual cycle of the expectant mother.

For example, if the cycle lasts up to 24 days, the baby can be born 1-2 weeks earlier than the due date calculated according to the formula mentioned above. If the duration of the menstrual cycle exceeds 32 days, the child may be "late" for the same 1-2 weeks, while such a "delay" will not be considered overdue.

How to calculate due date by ultrasound

Currently, the method of calculating the date of birth by ultrasound is the most reliable. It is only necessary to pay attention to the period of pregnancy in which the study is performed.

For example, if an ultrasound is performed at the 11-14th week of pregnancy, the expected date of birth can be set with an error of 1-3 days.

In the first trimester of pregnancy, the embryos practically do not differ in size. During the second trimester, differences in fetal weight and height can be quite significant, and in the third trimester they become even more pronounced. Therefore, during the 2nd and 3rd trimester, it is unlikely that it will be possible to find out at least the estimated date of birth by ultrasound.

By the first move

At a time when medicine did not yet have the means to conduct ultrasound examinations, the most reliable way to establish the expected date of birth was the method of determining the first movement of the baby.

Doctors are still interested in the date of the first movement of the child in pregnant patients and note this information in the exchange card, but this day is no longer given such importance. But no one is stopping you from trying.

In accordance with this method, women who are pregnant for the first time most often feel the movement of the fetus at the 20th week of pregnancy. Consequently, by the day of the first stirring, you need to add the same number of weeks. This will set the expected date of birth.

In the second and subsequent pregnancies, the first movements may appear as early as the 18th week. To determine the expected date of birth in such a situation, you need to add 22 weeks to the day of the first movement.

This method can hardly be called the most accurate. Due to the individual characteristics of physiology, some pregnant women feel the movement of the fetus earlier than the indicated dates. In addition, many modern mothers lead an active lifestyle, against which the moment of the first stirring may simply not be noticed.

In the event that a woman is forced to adhere to bed rest for medical reasons, she will certainly feel the movement of the fetus. At the same time, the first movements can be noticed by such women even before the 18th or 20th week.

According to the results of a gynecological examination

During a gynecological examination, the specialist notes the degree of enlargement of the uterus. In accordance with this indicator, it is possible to accurately determine the approximate day of delivery. The uterus increases in size along with the fetus, which is why an experienced specialist in most situations can calculate the approximate date of birth without any problems.

According to the size of the uterus during the first trimester of pregnancy, the doctor can determine the length of the pregnancy and therefore calculate the approximate date of delivery, using the approximate day of the last menstruation in the calculations.

On the 2nd and 3rd trimesters, it is very difficult to establish the date of birth based on the results of a gynecological examination, because. in different women, the size of the uterus changes with different intensity. In view of this, this method is considered ineffective in late pregnancy, and therefore is not used.

According to the results of an obstetric examination

In the second half of pregnancy (usually starting from the 20-21st week) during each gynecological examination doctor measures pregnant woman and the height of the bottom of her uterus. Thanks to these measurements, the specialist has the opportunity to monitor the course of pregnancy and timely determine the presence of any kind of abnormality. Also, thanks to this information, the doctor can approximately calculate the date of birth.

However, this method cannot be completely trusted, either. the accuracy of the readings obtained as a result of an obstetric examination may depend both on the individual characteristics of the pregnant woman's body and on the accuracy of the doctor.

What is the most efficient method?

The most effective method for determining the expected date of birth is the ultrasound method. Also, a relatively high accuracy is shown by the method of counting from the date of the last menstruation. It is very good if the results of the calculations for these two methods coincide - then the chances of the baby being born on the expected day will also increase.

But if the dates do not match, you should not be upset. Carefully monitor the course of your pregnancy and regularly undergo scheduled examinations. Remember: each of the considered methods allows you to determine only the approximate date of birth.

Why are due dates only estimates?

In reality, it is almost impossible to establish the exact date of birth of a child. Only a few women manage to give birth exactly on the day determined by the doctor or on their own. Most often, pregnancy lasts 280 days (40 weeks), but it is not uncommon for mothers to give birth at 38 weeks or even earlier, and in many situations this is considered the norm. Moreover, if a woman is pregnant with more than one child at once, then, in most cases, she will begin to give birth earlier than the date set by the gynecologist.

It is important to understand that a child can be born 1-2 weeks later than the due date - this is not considered a deviation in most situations.

That is, a deviation from the "standard" 40 weeks by 1-2 weeks forward or backward is not considered something abnormal.

It is important to understand the fact that a variety of factors can influence the duration of pregnancy and the approximate day of delivery. So, for example, various diseases and complications can lead to premature birth.

Thus, in the absence of complications, the child is born only fully mature and ready for life outside the mother's womb. It is almost impossible to accurately calculate the date of birth. But the above methods, as well as our calculator for calculating the date of birth online, will help you set the estimated or approximate date of birth.

Health to you and your baby!

Pregnancy is a long-awaited and desired event for many women. And now it will be interesting for you to find out everything about your situation: how pregnancy develops by weeks, what happens in the body. And it is with the help of the pregnancy calendar that you can do this very quickly and easily.

Pregnancy Calendar is a convenient and useful service for future parents of moms and dads, which will tell you in great detail about pregnancy by weeks. He can be your companion throughout the entire period of pregnancy up to the birth itself.

Pregnancy is divided into 3 trimesters:

First trimester - 1-13 weeks after conception
Second trimester - 14-26 weeks
Third trimester - 27-40 weeks

How does the fetus develop during each trimester? Our pregnancy calendar will give you the answer.

Why you need a pregnancy calendar

The pregnancy calendar will tell expectant mothers about how their baby changes and grows at one time or another, how its organs develop, how the baby gains weight. Our pregnancy calendar will tell you what to do and what to abstain from at each stage of pregnancy, which doctors to visit, how to eat and what lifestyle to lead so that your baby is born healthy.

Also, our online pregnancy calendar will help you find out in which week with the help of ultrasound you can determine the girl you have to be born or the boy.

It is this weekly pregnancy calendar that gynecologists use when determining the age and development of the fetus. But there is also the age of the fetus, which differs from the menstrual period of pregnancy by 2 weeks.

In addition, this online pregnancy calendar allows expectant mothers to communicate and share their feelings and impressions with friends in an interesting position every week of pregnancy. Leave your comments and you will find out who has the same feelings and what they can mean.

But you need to know that the body of each pregnant woman is different, and our calendar does not take into account the individual characteristics of the menstrual cycle, so the calendar contains general information for everyone. All dates are approximate, as the length of the menstrual cycle varies from woman to woman and can vary, as a rule, from 24 to 36 days. In addition, you need to take into account the fact that the cycle may be irregular.

Reviews

Galina Chalay
I approached the moment of conception very consciously and, of course, I take my pregnancy responsibly. It is very important for me to know what happens to the baby at each stage of his development. After all, from the moment of conception, he is my child, whom I must take care of. Therefore, I always look with pleasure at the pregnancy calendar and read how my son lives in my tummy.

Natalia Semerichko
For me, the most important thing was that by reading about my week of pregnancy, I could chat on the forum and discuss feelings with other expectant mothers who are at the same time.

Maria Krylova
This calendar helped me learn a lot of useful information about my future baby. During this period, I was most interested in how he was in my tummy. After all, this was my first pregnancy. Very convenient and helpful service. Thanks a lot!

Send your feedback about the Pregnancy Calendar to [email protected] website

How to calculate due date

Stanford University adheres to the following calculation formula:

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

For example, your first day of your last 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 the alert, therefore it offers a new service - an interactive pregnancy calculator, designed specifically for you.

With the help of our calculator you will be able to accurately calculate the date of delivery and all the main points of your pregnancy. The calculation will take only a few seconds, the page will refresh and you will receive your weekly pregnancy calendar. Now you will know exactly when the baby will be able to move his fingers, respond to your touch, hear your voice.

If it seems to you that you became pregnant earlier or later than your menstruation, then after a planned ultrasound scan you will be able to calculate the gestational age again, 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 date of birth.

Benefits of using
pregnancy calculator:

Every woman with the onset of pregnancy has many questions. When will the belly start to grow? When will the baby start moving? When do I need to register at the antenatal clinic and when can I go on maternity leave? When can we expect the baby to be born? All these questions can be answered on our website. We have described for weeks 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 dates of each trimester, significant dates (conception, childbirth, prenatal leave);

The doctor at the reception will definitely ask about changes in the woman's condition. With the help of a calculator it is very convenient to look at what to look for, at what time certain symptoms should appear;

An obstetrician-gynecologist will definitely draw up an examination plan, tell you which week you need to take certain tests, do an ultrasound scan and other instrumental studies. An 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.

The online pregnancy calculator is a handy service that helps a woman to have a clear idea of the course of pregnancy and the sequence of events.

Approximate calculation for the average cycle duration and the onset of ovulation - plus 14 days to the beginning of the last menstruation.
Full 40 weeks.

The online pregnancy calculator will help you calculate the gestational age, determine the expected date of birth, calculate the age of the fetus, and find out when the end of the first and second trimesters will come. The pregnancy calculator is a free service. Depending on the individuality of the organism, some data may not match.

Each pregnant woman keeps her own calendar, where she records all the changes that occur to her during pregnancy. However, the modern pace, a lot of family concerns do not always allow you to track on your own what week of pregnancy is going on and how the baby should develop. A pregnancy calendar comes to the aid of busy mothers: this is a complete description of all the changes that are happening at this stage with mom and baby. Thanks to this, a woman can easily track how much the baby weighs, what she should feel, what problems await her. But in order to find out how the child develops, you need to determine what the woman's gestational age is.

First day of last menstrual period:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 January February March April May June July August September October November December 2018 2019

Average cycle time (days):

22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45

Calculation results

- Estimated date of conception

- Fetal age

- Gestational age

How to find out the time of conception?

Traditionally, in order to determine what the current gestational age is, a woman comes to the antenatal clinic in the clinic. The doctor conducts an examination, if necessary, prescribes an ultrasound and focuses on the last menstruation in the setting of the term. Based on this date, a calculation is being made when the mother should give birth.

But it is worth warning women that such a calculation will not always tell you the exact day of delivery. In medicine, there are two terms for determining pregnancy: obstetric and real. What is their difference?

The obstetric term helps to determine when the pregnancy began, based on the date of the last menstruation. In this case, the date of conception is not taken into account, since it is unknown to the doctor. The doctor proceeds from the concept of a woman's standard menstrual cycle, which lasts 28 days. Therefore, conception could occur during ovulation on the 14th day after the start of the cycle. It turns out the difference between the obstetric period and the embryonic period by 2 or even 3 weeks.

You can find out the real time more precisely if you undergo an ultrasound scan. However, ultrasound is prescribed no earlier than 10-12 obstetric weeks, and the woman's curiosity is much stronger.

How can you find out your own gestational age in order to subsequently focus on the calendar?

To do this, it is desirable to know the date of conception, or at least the possible days when this could happen. If you cannot set the date, you can use reusable pregnancy tests. The devices are equipped with sensors that determine the gestational age. The error of such devices is small.

You can calculate the gestational age on your own, based on the obstetric calculation method. But if this is difficult for you, an online calculator will come to the rescue. This is a program on the site that will calculate the approximate date of your ovulation and, therefore, the expected date of conception.

How does the calculator work, and what is needed for this? You just need to enter the first and last date of your period. The online calculator itself will calculate the middle of the term and determine the date of conception of your child.

If you know the date of conception, an online calculator will also help determine the time when pregnancy occurred. The way it works will be different. You need to enter the date of conception into the calculator, and it will calculate the gestational age by weeks. So you will know exactly which week goes on what dates you have, and you will be able to observe from the descriptions how your child grows.

When is the birth?

Now is the time to find out the due date. The same calculator that determined the date of conception will help you calculate the date of birth. The online calculation is based on the data on the date of conception or the last menstruation. In the latter case, you will know the due date based on the obstetric term.

If you know exactly how many weeks you have, then you can guess from when to expect the onset of labor. This usually happens at 38-40 weeks. Some women live up to 42 weeks: such a pregnancy is not considered post-term. It should also be noted that an error could occur when determining the gestational age. An online calculator can also make a mistake, as it calculates based on generally established observations. In addition, you could enter inaccurate data into it.

Practice shows that the date of birth is the date of the beginning of the last menstruation, to which 9 months are added. In these numbers, we should expect the completion of the family. But what to do if it is not possible to determine the period by menstruation, since the woman no longer remembers the exact date?

HCG analysis

If a woman does not follow the regularity of the cycle and does not remember the date of the last menstruation, the calendar is unlikely to help here. In this case, doctors recommend doing a blood test for hCG, a hormone that allows you to determine the presence of pregnancy even in the early stages.

HCG (chorionic gonadotropin) is produced in a woman only during pregnancy with a fetal egg. A biochemical blood test is able to determine its amount in the body and, on the basis of this, establish the presence and duration of pregnancy. The most informative are the first 12 weeks of pregnancy, when the level of hCG is still high. Gradually, it begins to decline, and a blood test will no longer give reliable data.

Approximately determine the size of the fetal egg, and according to it - what is the current gestational age, the doctor can also when examining the vagina and palpation.

Why do you need to know the exact date?

Not all women are attentive to their pregnancy and calculate the period by weeks. They think that it is the task of the doctor to calculate the gestational age in order to subsequently calculate the date of birth. During pregnancy, they do not think about how many weeks they have now, and how the baby should develop.

In vain, since no one better than the mother herself will determine whether the baby is comfortable inside. Dangers lie in wait for a pregnant woman at every turn, and it is better if she knows her due date by weeks. A calculator and a calendar can help with this, so it is not necessary to ask a doctor every time.

If you do not know how many weeks of pregnancy you have, open the calculator on the site, enter the required data, and you will receive an answer. It will help you remember the doctor's recommendations and warn yourself and your baby against possible complications. Isn't it nice to see in the photo and video how your baby is growing week by week? After all, you can only look inside with the help of ultrasound, but this happens only three times during the entire pregnancy.

The need to undergo screenings is another reason why a woman needs to know the exact gestational age. Studies, including a blood test for genetics and ultrasound, take place within strictly defined terms. If you do the analysis sooner or later, you can get an inaccurate answer.

Do not neglect the calculation of the gestational age by weeks. This will give the woman valuable material to determine if the baby is developing according to the norm, if there are any deviations, and what studies still need to be done.

What errors are possible?

Unfortunately, if the exact date of conception is not known, any weekly pregnancy calendar or conception calculator may not be accurate. The baby development calendar is based on the data that was originally determined. What if they are incorrect?

Unfortunately, errors cannot be avoided. According to statistics, in almost 20% of women during pregnancy, the difference between obstetric and embryonic terms is 14 days. If a woman's cycle is long, such as 35 days instead of 28 days, ovulation may only occur on day 21. Consequently, the difference between the obstetric term and the real one will be even greater. 1 week of the embryonic period will be equal to 5 or 6 obstetric weeks.

But even in the formulation of the embryonic period there is an error. It is several days, since the sperm can be stored in a woman's body for 3 days, so fertilization could not occur on the day of ovulation, but later.

Calculating the gestational age is a painstaking task. Not always a calculator and even a medical analysis can give an accurate answer. A woman should listen to her own feelings: they will help her find out by feeling what the gestational age is now, and how correctly the doctor determined it.

In order not to miss the fact of pregnancy and know exactly when fertilization happened, a woman should be attentive to the signals of her own body and conduct regular monitoring of her health. To do this, you need to keep a calendar where the dates of the beginning and end of menstruation, the facts of suspicious vaginal discharge (if any) will be recorded. This will allow you to establish the onset of the disease in time and avoid consequences for yourself and the child.

To be healthy and give birth to a healthy baby, a woman must be attentive to herself. The calculator on the site and the pregnancy calendar will help her with this!

The need to calculate the gestational age by weeks occurs in almost every pregnant woman and more than once during pregnancy. And this is necessary not only in order to simply know your due date or correctly track the pregnancy calendar. I also want to calculate the duration of pregnancy and childbirth in order not to doubt the correctness of the doctor’s actions, if they make a mistake in the consultation - this can also affect the date of going on maternity leave, you don’t want to work an extra couple of weeks, right?

First, some general information.

Our calculator will help you calculate the obstetric gestational age, it is slightly different from the actual life of the fetus. Gynecologists build all their calculations on the date of the first day of the last menstruation, and do not count from fertilization, this is due to the ease of error in the date of conception.

Ovulation in a woman can significantly shift in time, especially if she does not have a regular cycle, and of course, not everyone can know the exact date of fertilization, it is difficult to calculate the gestational age by ovulation. And the date of the beginning of the last menstruation, as a rule, is known.

We have a special calculator that allows you to independently calculate the gestational age online. He will give you information not only about the obstetric gestational age, but also the date of conception, the age of the fetus, the date of birth.

The problem may arise if yours is not regular. How to correctly calculate the gestational age by menstruation with an irregular cycle? You need to add the length of the last 6 cycles and divide by 6, so you get the average duration, this is the number of days and you need to enter in the calculator field.

All data obtained can be easily controlled using other calculation systems.

You can accurately calculate the gestational age (well, or relatively accurately, as gynecologists think) using the Negele formula. It does not take into account the length of your cycle and therefore the result may differ from the period that our calculator gives, but this will certainly coincide with the calculations of the gynecologist: we subtract 3 months from the first day of the delay in menstruation and add 7 days to the date obtained. This is your due date. Calculate the gestational age by months, weeks and days, as with our calculator, using this formula will not work.

If you had an ultrasound, the doctor measured the development of the baby. Its weight, the length of the bones make it possible to calculate the gestational age by ultrasound, but this calculation is accurate only in the first trimester, the longer the period, the greater the difference in physical development in different children, and the higher the risk of error in determining the timing of pregnancy.

Almost all calculation methods carry a certain risk of error, which is why only 4% of children are born on the PDR (preliminary date of birth).

It is better to evaluate the results of calculations in a complex (ultrasound, date of the last menstruation, first movement and other dates and signs). And still, the date of birth can fall between 37 and 42 weeks of pregnancy.