Calculator for calculating the due date and gestational age

When does this happen?

The date of conception is the day when the parent sex cells merged and exchanged genetic information. As a result, a separate, unique cell with its own genome was formed - a zygote. Your child will grow out of it in 9 months.

Conception is possible only during a limited period of the female menstrual cycle - while the egg is alive and productive. It should be noted that it matures inside the follicle during the entire first half of the cycle, and under the influence of hormones on the day of ovulation, the membrane of the vesicle ruptures, releasing the female gamete. From this moment on, she lives from a day to a day and a half. If the egg does not merge with the sperm within 36 hours, the female cell dies, and conception becomes impossible in this cycle.

If we consider conception as a complex process of fusion of sperm and egg, then it is technically and physiologically possible only within 24-36 hours after the release of the egg.

Even if a woman knows exactly the day of ovulation (which is quite rare), it is completely impossible to understand when exactly the fusion (conception) occurred. It could happen immediately after the oocyte leaves the follicle, an hour later, a day later, or 30 hours later. Agree, a spread of almost one and a half days is not the most accurate indicator.

Some women are sure that the date of conception and the day on which sexual intercourse took place are one and the same. This is wrong. Male reproductive cells have greater viability and can steadily expect ovulation, having already been in the genital tract for 1-4 days. Thus, sexual intercourse performed 4 days before ovulation can cause pregnancy. With the same success, the cause of conception can be coitus performed on the day of ovulation and within 24 hours after it.

Whenever sperm enters the female reproductive tract, conception will still only occur during the period of ovulatory viability of the oocyte indicated above.

Women's calendar

As a rule, every woman (since adolescence) keeps her own personal women's calendar. It reflects the features of her menstrual cycle:

- 1st day of menstruation,

- last day,

- their duration,

- day of ovulation,

- days suitable for conception,

- unsuitable.

That is why all the marks in this calendar are important and necessary data for both any woman and her life partner when planning their relationship and future together. The information contained in this women's calendar will be especially useful for planning a possible pregnancy and procreation.

A woman can create her own personal conception calendar:

- independently, having calculated all the days;

- using available special online programs on the Internet.

How to make a calculation?

As you can see, it is not possible to calculate the exact day when the child was conceived. But you can determine an approximate range:

• knowing that ovulation occurs on average 14 days before the end of the cycle, subtract 14 from the cycle duration;
• We add a day to the resulting day - we get the range of possible conception.

This is quite arbitrary. After all, ovulation could be early or late, and such calculations in no way take this into account. But the date of conception, on the other hand, has no diagnostic value in the management of pregnancy and childbirth, and therefore doctors are content with just such a calculation. It is believed that the gestational (embryonic) period is two weeks (14 days) less than the obstetric period.

With the obstetric period it is even simpler - it is counted from the first day of the last menstruation. This is the first day of pregnancy. Now it is not difficult for you to independently calculate your gestational age, and by subtracting 14 days from it, get the approximate date of conception of your child.

Important! The woman undergoes all tests, descriptions, and examinations exclusively according to the obstetric period, determined by the last menstruation.

The date of conception is of no value either when undergoing an ultrasound scan or when determining the expected date of birth (EDD).

Conception calendar online

If the previous method of studying and drawing up a conception calendar for a long time does not suit you, you can resort to online programs that create a personal schedule based on your menstrual cycle data. There are plenty of such programs on the Internet; as a rule, you need to indicate the 1st day of menstruation and the duration of the cycle. As a result, you will be offered a calculated calendar several cycles ahead indicating ovulation, favorable and unfavorable days for conception and safe days for sex. Do not forget to carefully read the comments of the creators of this program, if any. It would not be amiss, if you have seriously decided to approach pregnancy planning, to consult a gynecologist with your existing calendar in order to receive additional recommendations or amendments.

How to use the calculator?

Modern online calculators allow you to calculate all the necessary deadlines quickly and without arithmetic errors. You just need to indicate the start date of your last menstruation, and in a matter of seconds the service will answer the question of what time it is, when to give birth, when the baby was conceived (presumably!), and will also provide a lot of information useful during pregnancy - about the development of the baby, about the necessary examinations , about physiological changes in the maternal body characteristic of a particular period of gestation.

You can print out a detailed calendar of your pregnancy and refer to it.

Some services and applications allow you to get advice from specialists (doctors, social workers, psychologists) online.

Calculators work for free. Applications that you need to download and install on your mobile device may contain paid content.

How do features of the menstrual cycle affect the date of birth?

The duration of pregnancy is influenced by a woman’s menstrual cycle, or rather its duration. If this indicator is more than 28 days, then you will have to carry the child for more than forty weeks; this principle also works in the opposite direction. It is important to consider that the deviation is no more than 5 days.

The method has a large error, since expectant mothers may confuse banal bleeding that occurs after conception with menstruation.

Special cases

If a woman has an irregular cycle, a calculator will be of little help, especially if she does not remember the date of her last menstrual period. In this case, at up to 10-12 weeks it is important to do an ultrasound. It is during the first trimester that its results for determining the due date are most accurate.

This is due to the fact that all embryos develop at approximately the same speed, and after the end of the embryogenesis period, each baby begins to grow according to its own hereditary program given by the parents. In the early stages, the doctor can determine the due date based on the size of the fertilized egg within a few days.

Please note that the data in the ultrasound report is presented in obstetric weeks; in order to correctly understand when the approximate date of conception was, it is important to subtract 14 days from the indicated period.

For women after IVF, the question of calculating the date of conception does not arise at all. The conception was carried out by specialists - embryologists in the laboratory, it was controlled by doctors, and its date is absolutely known. But other questions may arise, for example, how to calculate the date of birth and gestational age. In this case, you should use a special calculator in which you need to indicate the date of transfer of the embryos into the uterus and the age of the embryos in days at the time of transfer. The program can calculate the rest as accurately as possible.

Sometimes you can come across a question that seems strange at first glance: it is usually asked by men who doubt their paternity - is it possible to calculate when a child was conceived by the date of birth. This is even more difficult to do than during pregnancy. Here's why: pregnancy lasts 288 days on average. But a normal full-term pregnancy can end in childbirth at 38 weeks, 39 weeks, and 42 weeks, and not just on the day of pregnancy (end of 40 weeks). Therefore, the very date of birth of a child cannot indicate exactly when he was conceived. In this situation, it is better to turn to geneticists and do a DNA test to determine paternity.

medical reviewer, psychosomatics specialist, mother of 4 children

Source of the article: https://o-krohe.ru/beremennost/rasschitat-datu-zachatiya/

What happens after conception?

You should know that pregnancy occurs on average within 10 days after fertilization of the egg. It is during this period that the egg leaves the tube into the uterine cavity and attaches to its surface. During this period, a woman may notice certain changes in her body, which gynecologists classify as signs of 1 week pregnancy.

After the egg has entered the uterus, the woman’s body intensively begins to produce a hormone, without which it is impossible to bear a child. In gynecology, this hormone is known as human chorionic gonadotropin, or hCG.

The main purpose of this hormone in the 1st and 2nd trimesters is to maintain the vital activity of the corpus luteum, which secretes progesterone. If there is a lack of progesterone in the body of a pregnant woman, the threat of interrupting the process of bearing a child increases.

Human chorionic gonadotropin found in a woman’s blood is the main sign of pregnancy 2 weeks after conception. It is at this time that, as a rule, a blood or urine test is taken.

Women sometimes try to determine the presence of hCG in the body with the help of special tests, using them at home. But the results obtained are not always reliable, which is due to the low sensitivity of the test.

How to calculate the gestational age based on the date of conception? Online calculator

An online calculator allows a woman to accurately calculate the duration of her pregnancy and set the expected date of birth of the baby. The calculation does not take much time, and usually a single value is used for it - the start date of the last menstruation. At the same time, there are women who believe that they know exactly the date of conception of the baby, and therefore they are interested in how to calculate the period based on this date. Let's talk about this in more detail.

Methods for determining ovulation

The date of birth is determined by the date of ovulation. Based on the yield of a mature cell, the PDR can be calculated. The day at which fertilization is possible is calculated using the following methods:

1. Express tests. You must first read the instructions. The strip is dipped into the urine for a couple of seconds, after which the color of the control reagent changes. The principle of the test is based on determining the level of luteinizing hormone, which is released after the egg leaves the follicle.
2. Microscope. A reusable device that allows you to analyze salts in saliva. The image gradually changes, by the time of ovulation it resembles a fern.
3. Discharge. During the development of the follicle, vaginal mucus has a thick consistency, but on day “X” it thins out and is released in large quantities. In appearance, it resembles egg white; discharge continues until the cell dies.
4. Painful sensations. The pain is localized in the area of ​​the ovary. When the egg ruptures the follicle, a wound remains in its place, which causes discomfort.

Based on your own feelings, you can easily determine the day when conception could have occurred. Based on this, calculations are made for the expected duration of pregnancy.

How is it usually counted?

All over the world, it is customary to calculate the gestational age in obstetric weeks. This unit of time is very important for expectant mothers and their doctors. The obstetric week is no different in duration from the traditional one; it lasts 7 days. But the duration of the obstetric month is different. Instead of 30, 31 days, as in the calendar, one obstetric month has exactly 28 days (4 obstetric weeks).

The calculation of the period in obstetric weeks does not begin from the date of conception, not from the date of ovulation, not from the date of delay. The only date that starts the countdown is the day the menstruation begins, preceding the “fetal” cycle. This day is the first day of pregnancy. You shouldn't be surprised. Yes, in fact there is no pregnancy yet, but the woman’s body is preparing for it with all its might - the egg matures, on the day of ovulation it leaves the follicle and is fertilized. From this moment the actual, embryonic period of pregnancy begins.

Why not count the dates in it, because it seems more logical: 1 week of pregnancy is the first week of the baby’s life, 2 weeks is the second, and so on. Maybe it would have been this way, and indeed it would have been more convenient, if it weren’t for this great and insurmountable difficulty - it is impossible to establish the day of conception. The only exception is IVF - there the day of fertilization is known for sure, since fertilization takes place in the laboratory under the control of embryologists in a Petri dish.

Conception occurs at the moment of ovulation and within a day and a half after it. This is how long an egg lives. Then she dies if fertilization does not occur. Fertilization is no longer possible either before ovulation or 36 hours after it. Therefore, it is difficult to understand what sexual act can lead to the birth of a new human life.

Sperm can live in the female genital tract for up to 3-5 days. If sexual intercourse took place before ovulation for such a period of time, it is possible that the sperm will wait until the oocyte is released, and fusion will immediately take place. If the act is performed on the day of ovulation, then fertilization can occur within an hour after that, and within 36 hours - it all depends on the quality of the sperm and egg. As you can see, even if there was only one sexual intercourse during the month, it is no longer possible to name the exact day of conception.

And if a woman lives a normal sex life, regularly, then the date of conception is even more difficult to establish. That is why doctors count from the only date that is not in doubt - the date of menstruation. Online calculators and apps calculate deadlines in the same way.

Conception calendar: calculate

To independently create a conception calendar, a woman should analyze her menstrual cycle and determine the ovulation day. How to do it?

Let's give an example. For specifics, let’s analyze a certain woman’s stable menstrual cycle of 28 days with 5 monthly days and calculate the conception calendar for her. With a stable cycle length of 28 days, ovulation will occur on the 14th day. The day of ovulation is actually the day of conception, that is, the probability of fertilization and pregnancy on this day is the highest possible. Favorable days for pregnancy are the 5 days preceding ovulation, as well as 12-15 hours after ovulation itself. An unfavorable time for conception is considered to be the period of menstruation and a couple of days before its onset.

However, this method has a peculiarity. When constructing a calendar table, you need to take into account data on the menstrual period for the last 7 - 12 months. When forming a reliable conception calendar, cycle regularity is important.

If a woman’s cycle is unstable, then you can resort to another calculation:

1) Take data for the last 7 months and pay attention to the duration of the longest and shortest cycles.

2) From the duration of the shortest cycle (let’s take 24 days for our example), you need to subtract the universal number 18 (it does not change): 24-18 = 6. The resulting indicator reflects the beginning of days favorable for conception. In this case, the good period begins on the 6th day of the cycle.

3) Now you should take the number of days of the longest period of the cycle over the last 7 months (let there be 30 days) and subtract 11 from it - another universal number: 30-11 = 19. That is, the 19th day of the cycle ends the favorable period for pregnancy.

In other words, your chances of getting pregnant will be greater during the period from days 6 to 19.

By the way, if the cycle is irregular for a long time, you should definitely determine the reasons for this by contacting a specialist.

We determine the deadline and delivery date

Even if you have your own ideas about the date of conception, when calculating the period with a calculator, you should indicate the date of the start of the last menstruation - this way you will receive your current pregnancy period indicating the week, day, trimester, number of days until birth and the PDA itself.

The calculator determines the expected date of birth as the end of the 40th week of pregnancy. Doctors calculate it in the same way. You can calculate it yourself:

• to the first day of the last menstruation, add nine months and subtract 7 days;
• from the first day of the last menstruation, subtract three months and add a week;
• add 280 days to the first day of the last menstruation.

It is difficult to calculate the gestational age based on the date of conception, but you can estimate the expected date of birth if you are sure of the date of conception. Your due date at conception is determined by adding 266 days to your date.

Important! It is not necessary that your baby will be born on the exact day you receive as a result of the calculation. Birthday is an approximate guideline, but not an exact birthday.

Full-term babies are born any day from 38 weeks of pregnancy to 42 weeks inclusive. And this is a whole month. And not a single doctor can tell you exactly what day your birth will take place, because this process depends on the readiness of the body of the mother and baby.

Principles and algorithms for calculating the due date

To determine your due date, you can use an online calculator, consult a specialist, or make your own calculations. In any case, each of these methods has similar principles and algorithms.

One way to calculate the expected date is to draw up a weekly pregnancy calendar if the date of conception is known. As a rule, it is very difficult for a young couple to remember the exact day of fertilization. By following simple steps, you can independently determine when pregnancy has occurred. It is necessary to consider the process of childbirth in a woman:

1. The formation of vesicles in the ovary occurs only after menstruation. The intensity of development of one of them exceeds the others, and a female cell appears in it. The growth of other follicles is gradually inhibited.
2. At a certain point, the cell reaches its maximum, breaks through the follicle and begins to move towards the uterus. If there are favorable conditions on its way, contact with the sperm occurs. The time of successful penetration of the male seed into the egg is considered conception.
3. The egg continues to move and attaches to the wall of the uterine space. This will happen no earlier than in a week.
4. If implantation takes place without disturbances, then the fetus develops and increases in size. This process is influenced by progesterone synthesized by the corpus luteum, a temporary gland that forms at the site of follicle rupture.
5. Under the influence of progesterone, the structure of the mammary glands changes. The first signs of an interesting situation appear.