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How many days from conception to birth? How to determine the date of birth?
How many days from conception to birth? How to determine the date of birth?

Pregnancy is the most beautiful, exciting and responsible time at the same time. It is pregnancy that teaches a woman to wait. Wait for the most wonderful and magical moment - the moment of meeting your baby. I want to “be fully armed” and prepare for it in advance. Therefore, the question: "How many days from conception to birth?" - interested in every expectant mother. Some pregnant women bother doctors with this question, but in response, even the most experienced gynecologists only shrug. They are doctors, not fortune-tellers. And they are responsible for their words. And no one can name the exact date of birth.

EDD - estimated due date

Estimated date of birth (EDD) can be calculated by yourself. Just remember that any forecast in this case will only be indicative. Be prepared for the fact that your main date with your son or daughter (or maybe twins) will happen a couple of days or even weeks earlier or later than the date received in the calculation.

Let's look at the most popular ways to calculate how many days from conception to birth you have to wait.

how many days from conception to birth

Pregnancy and its stages

Before calculating the EDD, it is worth understanding and understanding how a child develops from conception to birth and how long a pregnancy lasts on average.

According to statistics, in 80% of cases, the duration of a he althy pregnancy is about 38 weeks. This is about 266 days. It would seem that this is it! The time from conception to delivery is 38 weeks. What is there to count? But the main problem is that few people can accurately name this very date of conception.

Every week of pregnancy is a new stage in the life of the baby. Let's briefly consider what awaits a woman from conception to childbirth by weeks.

Pregnancy from the first to the twelfth week

A woman finds out what is waiting for a child after a delay in menstruation. But by this time, changes had already taken place in her body. The fertilized egg found its place and attached itself to the walls of the uterus.

In the third week of pregnancy, the zygote (fertilized egg) already has 32 cells and begins its movement through the fallopian tube into the uterus. The placenta is formed - the link between mom and baby. With her help, the baby will receive food throughout the pregnancy.

how many days pregnant

From 4th to 7th week there is an increased growth of the embryo. This is the time to "lay the foundation" of a new person - the nervous and circulatory systems, the skeleton, the heart and the brain are being formed. The growth of the crumbs by the beginning of the 8th week is up to 13 mm. On ultrasound, you can distinguish his facial features. The process of formation of genital organs, hair and nails begins. Embryo startsmove.

Pregnancy from thirteenth to twenty-sixth week

A characteristic feature of the second trimester is the active growth of the embryo. The reproductive system begins to form, with girls developing ovaries and boys developing prostates.

The movements of the embryo become clear and coordinated. From the 17th week, a fatty layer develops on the body of the fetus, which is involved in metabolic processes. By week 20, the baby has a fully formed brain, limbs and sensory organs. The skin of the fetus begins to thicken, and a lubricant appears on it, designed to protect the delicate skin of the newborn.

At 25-26 weeks, the growth of the crumbs increases so much that it becomes cramped. During this period, the expectant mother begins to feel active shocks and movements of the baby in her stomach.

Pregnancy from the twenty-seventh to the fortieth week

From the 27th week, the third and final stage of pregnancy starts. How many days of pregnancy are left and what is the baby doing in the mother's stomach? How do you prepare for a meeting with mommy and the world? All these thoughts are constantly spinning in the head of every expectant mother.

Baby doesn't think about it. At this time, he is actively gaining weight, begins to open his eyes and distinguish sounds outside his "house". The active growth of the fetal brain continues. The subcutaneous fat layer of the crumbs is already fully formed.

From 31 to 33 weeks, the proportions of the fetus change - the head ceases to exceed the body, facial features become more pretty. Such active movements, as in the secondtrimester, mommy no longer feels. This is due to the fact that the baby sleeps more often and can even dream. The epithelium of the fetus is smoothed and acquires a pinkish tint.

due date by date of last menstrual period

The main task of the mother's body at the final stage of pregnancy is to help the child gain weight. In his lungs, the production of surfactant begins - a substance that will help the lungs of a newborn to open up and take the first breath in his life. Thus, by week 40, the baby is ready for life outside the mother's tummy.

In the table below, future mothers can determine which tests and studies, as well as new sensations from communicating with the baby, await them at each stage of pregnancy.

Pregnancy term

Characteristics of the stage

Required Research

From the tenth to the thirteenth week

The end of the embryonic period, the formation of the central nervous system.

Double test (free beta hCG and PAPP-A). Conduct risk screening for Down syndrome and Edwards syndrome.

Sixteenth to eighteenth weeks

Formation of the reproductive system of the fetus, fat layer.

Triple testing (alpha-feto protein, human chorionic gonadotropin and free estriol), biochemical screening for Down syndrome and Edwards syndrome and fetal neural tube defects.


Feeling the first shocks of the embryo in women who have already given birth.


Twentieth week

Sensations of fetal movement in nulliparous mothers.


Twenty-second week

The formation of the brain and sense organs is nearing completion.

Second ultrasound to measure fetal organs.

Twenty-fourth week

Thickening of the endometrial layer, formation of original lubrication.

Dopplemetric analysis - determination of blood flow in the placenta.

Twenty-sixth week

The baby has noticeably increased in size and is a bit cramped. Therefore, mommy hears more and more of his pushing and twirling.

O'Sullivan test or glucose tolerant testing (to exclude the development of diabetes in the fetus).

Twenty-eighth week

The second trimester is coming to an end. There is a risk of preeclampsia or late toxicosis in pregnant women.

Arranging prenatal leave

Thirtieth week

There are less and less pushes of the crumbs, as he spends most of the day in a dream.

Mommy goes on vacation

Thirty-second week

Production of surfactant - a substance that helps the baby take the first breath

Third ultrasound to determine the condition of the placenta and baby

Thirty-eighth week

Term Pregnancy

Mommy getting ready to meet her baby

Now that we have got acquainted with the stages of pregnancy from conception to childbirth, and we know what happens to the baby inside the mother's belly, let's try to predict the date of the meeting with him.

Option one: date of birth according to the day of conception

The effectiveness of this method is debatable. This is due to the fact that women rarely know the day of conception. But doctors know for sure how many days from conception to birth pass on average. This is 280 calendar days. Therefore, if you can name the day of fertilization, then calculating the date of birth is not difficult. We add 280 days to the date of conception and get the desired result.

A possible error in the calculation of the EDD on the day of conception occurs due to the fact that pregnancy does not necessarily occur on the day when there was sexual intercourse. After all, the spermatozoon, being in the vagina, retains its ability to fertilize for several days. Divergence is possible in two or three days. Therefore, the calculated due date is an estimate.

Option two: due date by ovulation

Many people use the method of calculating due date by ovulation. The calculator is not for everyone. After all, only those women who have been trying to get pregnant for a long time track ovulation using tests or a basal temperature chart.

date of birth by movement

Estimated ovulation date falls in the middle of the cycle. For example, if the menstrual cycle is 28 days, then ovulation should be on the 14th. To this mid-cycle date, add 280 days, getting the estimated day of the baby's birth.

The accuracy of this technique is possible only if you have an ovulation diary and confirm it with tests.

Option three: date of birth by last menstrual period

This method helps you calculate your due date from your last period. This gestational age is called obstetric, and is usually longer than the actual gestational age.

There are two options for calculating the date of delivery by the date of the last menstruation:

  1. With the help of Nagel's formula. To do this, you need to discard 3 months from the start date of the last critical days, and then add another 7 days.
  2. Add 40 weeks (or 280 days) to the start date of your last period. Many practicing gynecologists resort to this practice.

Despite the popularity of this technique among obstetrician-gynecologists, its accuracy leaves much to be desired. Especially if the woman's menstrual cycle does not meet the average standard (less than 28 days or more than 30). How many days the pregnancy will last depends on how long her menstrual cycle is of the standard 28 days. Each additional day of the cycle lengthens the pregnancy by 1 day. But no more than 5 nights in total.

For women with irregular menstruation, this technique is not suitable at all. Popularization of the method among professionals is associated withby the fact that many more women can give the day of the last menstruation than those who can tell the day of ovulation or conception.

Often, the calculation of the date of birth by the date of the last menstruation is erroneous due to heavy implantation bleeding, indicating the attachment of a fertilized egg to the uterine wall. Many women mistake it for critical days, and the countdown of the due date starts on the wrong date.

An experienced obstetrician-gynecologist can determine the expected date of birth based on the date of visiting the antenatal clinic. You can confirm pregnancy with a doctor as early as 4 weeks. A full 36 weeks are conditionally added to this date. The use of such calculations is now becoming irrelevant due to the development of the pharmacy industry, which offers to determine the presence of pregnancy at home using tests. An increasing number of women prefer this method of establishing pregnancy. And they get registered in the LCD (female consultation) for pregnancy later.

Option four: date of birth by stirring

Another option allows you to calculate the date of birth by the movement of the fetus, that is, based on the date when it happened for the first time. Usually, in primiparous mothers, such a stir is felt starting from the 20th week of pregnancy. And for women who are preparing to become a mother for the second time or more - from 18 weeks. Adding the same number of weeks to the original date, we get the desired date of birth of the baby.

date of birth by ultrasound

This is perhaps one of the oldest ways to calculate the date of birth of the baby. In the absenceultrasound machine, he was considered not only the most reliable, but also practically the only one. When using this calculation method, it is worth remembering the following:

  1. The first movements of the embryo in the uterine cavity are fixed at 12 weeks of pregnancy, but they are so weak that the expectant mother does not notice them.
  2. Slender mothers leading a sedentary lifestyle are much more "sensitive" to tremors and fetal movements. Such women are able to feel the movement of the baby, similar to a light tickle, as early as 14 weeks of pregnancy. And overweight women are less sensitive in this matter.
  3. A woman carrying a pregnancy for the first time simply has no idea how exactly the movements of the embryo are manifested. As a result, they often do not attach importance to the slight turns of the crumbs in their tummy. Women who already have children are more experienced and notice them sooner.
  4. The visibility of the first movements of the embryo is also due to the thickness of the walls of the uterus. And this is a purely individual parameter.

If a woman is registered with a antenatal clinic, her gynecologist will definitely ask and enter information about the first fetal movement into the map.

Option five: due date by ultrasound

The most truthful answer to the question: "How many days from conception to birth?" - will give an ultrasound examination. With the help of an ultrasound machine, a specialist can determine the size of the fetal egg, according to which the gestational age is calculated.

time from conception to birth

From the 12th week of pregnancy, ultrasound measures the size of body partsbaby. But it also happens that the date of birth according to ultrasound does not coincide with the embryonic gestational age. Sometimes the difference between these values ​​​​is up to two weeks. Such discrepancies confuse the expectant mother and make her nervous. She is afraid of abnormal development of the fetus or miscarriage.

But there is no cause for concern. It is difficult to interpret the results of ultrasound. Often, an old ultrasound machine or an inexperienced doctor can “blur” the picture. In addition, the development of the crumbs is an individual matter and does not always exactly coincide with the generally accepted standard. But if the mother hears from the doctor that the head of the fetus corresponds to 23 weeks, and the heart is 26, it is better to seek advice from another specialist and conduct a new ultrasound procedure.

According to doctors, the most accurate picture of pregnancy on an ultrasound machine can be seen up to 12 weeks. This is due to the fact that the stages of fetal development during this period are most obvious. And from the 13th week, the development of each crumb goes according to its own scenario. Someone develops slowly and gradually catches up with the standards. The other is in a hurry to meet his mommy and is ahead of schedule.

When deciphering ultrasound screening, specialists correlate the data obtained with tables of fetal parameters. Do not get depressed if the obstetric and embryonic gestational age do not match. This is not a pathology, but a kind of normal.

from conception to childbirth by weeks

The most truthful forecast will be the date of birth with the greatest amount of known data. But if you can't name a single one- not scary. After all, the best things in life happen all of a sudden! And the birth of a long-awaited baby is no exception! What does a couple of days of waiting mean compared to the joy of meeting your baby and the opportunity to show him this world?!

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