How to determine the date of birth by the last menstruation: basic parameters, exact methods, reviews

2024 Author: Priscilla Miln | [email protected]. Last modified: 2023-12-16 00:21

Childbirth is a sacrament for every woman. For some, this is a long-awaited event filled with worries and cares, for others it is a period of worries and stress, for others it is a time of silence and spiritual harmony, and for some it is a natural process of continuing life. Despite how a pregnant woman relates to her situation, having learned about it, almost every woman wants to determine the date of the baby's appearance. The importance of correctly setting the date of birth is very important, because according to these terms, a detailed analysis of the state of the mother and her unborn child is formed. How to determine the date of birth by the last menstruation, as well as using other studies, will tell the following article.

Menstrual cycle and ovulation

Menstruation directly affects the timing of childbirth. You can determine the approximate date of birth by the last menstruation, given the length of the menstrual cycle.

By all rights, a woman's period lasts 28-32 days. Such a cycle is called the most normal and common in 60% of women of childbearing age. Given these numbers,ovulation occurs on the 12-14th day. The egg is released from the ovary and is ready for fertilization. But this cycle is not always perfect.

Stress, travel, illness, and even a simple runny nose can knock down a woman's clock, thereby reducing the likelihood of accurately determining both the day for direct conception and the timing of the upcoming birth.

In 30-35% of women, the menstrual cycle is not constant, and therefore there is both early (10-12 days) and late (18-20 days) ovulation. Such indicators affect the onset of both desirable (it is impossible to determine the day of ovulation, and hence conception) and unplanned (late and early ovulation in 50% are the cause of unwanted conception) pregnancy.

Ovulation pains and PMS

Despite all the shortcomings of obstetric terms, it is still the best option to determine the date of birth by the last menstruation. You can assess your condition if you listen to the body.

Many women, when planning a pregnancy, attach great importance to every sensation. So, when ovulation occurs, estrogen levels increase. And this is necessary not only for the egg to leave the ovary, but also for filling it with nutrients and vitamins that are necessary for conception and the formation of the fetus, and later for its development. With an increase in the level of this hormone and the release of the egg, many women experience pain that lasts from 3 hours to 1 day. These are the so-called ovulation pains, by which it is also possible to determine the onset of ovulation, andhence, the estimated date of the beginning of the gestational period.

After ovulation has occurred, the egg moves for about 24 hours, maintaining its function. At this time, progesterone is produced, which can help in fertilization. During this period, a woman feels chest pains, irritability or nervous excitement, anger. This is the so-called "premenstrual syndrome". If the egg is not fertilized, progesterone and estrogen levels plummet and menstruation begins.

So if a woman feels ovulation pains every month, she can know about the beginning of the fertile period (the most favorable days for fertilization) and thus know about the timing of conception.

Methods for determining the date of birth

You can determine the date of the long-awaited birth by various indicators.

• According to the last period, the date of the first day of the last period.
• Pelvic ultrasound, pelvic exam, and fetal development.
• By ovulation or fertile days.
• According to the day when conception occurred.
• At the first movement of the baby.
• According to the parameters of the uterus and the height of its bottom.

And there are a few tricks that are not scientific: by intuition, by the shape of the abdomen, by gaining weight, etc.

Each of the methods is quite relative and will never give a 100% guarantee that the child will be born on a given day. When calculatingtakes into account the data of the average woman with a constant menstrual cycle. For greater certainty, the timing takes into account the indicators of several surveys and formulas in the calculation.

Obstetrical and gestational timing of pregnancy

In modern obstetrics, as well as decades ago, there is a proven, most convenient way to determine the approximate date of birth by the last menstruation.

It is worth dwelling on the question of the accuracy of the terms of the pregnancy itself set by the doctor.

Often, some women confidently refute the terms of their pregnancy, which the doctor noted to her. A woman knows exactly when conception occurred. But unprotected intercourse does not mean conception that occurred at that very moment. In order for the sperm to fertilize the egg, it takes time and the egg itself, which comes out of the ovary during the period of ovulation. This happens approximately on the 12-15th day of the cycle. When all these factors combine, then pregnancy occurs.

If a woman follows all the changes in her body and plans pregnancy based on the time of ovulation, then she can calculate the term of birth according to the gestational schedule, which lags behind the obstetric one by about 2 weeks. That is, the obstetric period is determined from the day the last menstruation begins (about 2 weeks before ovulation), and the gestational period is determined from the day ovulation begins.

This method of gestational timing is only effective for a constant cycle and keeping an ovulation diary andbasal temperature. But not every woman resorts to such methods, so the obstetric method of calculation is more reliable.

But the most typical rule for setting the date of birth is the method of determining the last menstruation.

Negele's rule

The famous German doctor from Düsseldorf, Karl Frans Negele, developed in 1807 the principle of calculating the date of the upcoming birth according to the first day of the last menstruation of a pregnant woman. This formula is the most effective and most often used in obstetric practice. It is important to know that this method takes into account not the last, but the first day of menstruation. How to determine the date of delivery by the last menstruation?

1. According to the template formula, it is necessary to subtract exactly 3 months from the first day of the last menstruation and add 7 days to the resulting date. By changing the year to the next, we get the estimated date of birth. For example, if the last menstruation began on September 16, 2018, then, subtracting 3 calendar months, we get June 16, add 7 days and get June 23, change the year to the next one. The final date of the expected birth is June 23, 2019.
2. Modified method. 9 months and 7 days are added to the first day of the last menstruation. If we take the previous example, then the date will not change, that is, September 16 + 9 months=June 16, 2019 + 7 days=June 23, 2019.

Using the Naegele formula, obstetricians and gynecologists can find out the approximate date of birth from the last menstrual period. The fundamental factor here is the constancy of the pregnant cycle. The normal phase of menstruation lasts 27-29 days. If the menstruation goes astray, there are periodic delays or the start is too early, then it will be difficult to find out the date of birth from the last menstruation.

Determining the date of birth with a non-permanent cycle

With an unstable menstrual cycle, pregnancy can occur with an early release of the egg, and with late ovulation, and it will not be possible to determine the exact time of ovulation. In this case, the Naegele method is not effective. But still, the date of birth will be set primarily on it. Finding out the due date by the date of the last menstruation will not work exactly, but several examinations will tell you when to give birth. First, all calculations will be taken based on the annual cycle. It calculates the average length of the days of the female calendar, as well as the average duration of menstruation. As a result, the approximate period of ovulation will be calculated, and hence the period of conception. In addition, the data of the examination and ultrasound examination will be taken into account.

Why measure fundal height?

An important point in the additional study of a pregnant woman to set the term and date of birth is the early registration of a woman. In case of difficulties in determining the terms and dates, the data of the examination and measurements taken directly by the doctor are taken into account. Their accuracy and correctness depends on the early period of bearing a child. The earlier the first examination is made, the more accurately the term of delivery is set. The doctor conducts a special examination, measures all the necessary indicators with a centimeter, including size, density and standing heightthe bottom of the uterus, according to the parameters, the gestational age is set. The higher the bottom of the uterus, the sooner the birth will come. The doctor usually measures the abdomen, feeling for the necessary female organ. The upper point of the uterus is easily located, and an experienced doctor cannot confuse it with anything, so the study is quite accurate.

Ultrasound

At the ultrasound examination, the gestational age and the date of birth are specified according to the parameters of the fetus itself. Not only fetal indicators are measured, but also the condition of the uterus, placenta, etc. Do not forget that all indicators are taken from the average pregnancy. And you should not panic if the size of the baby differs from those indicated. Each child is individual and unique. Reviews and stories of mothers who gave birth confirm this. Some say that only the first ultrasound examination, which is performed at the 12-14th week of pregnancy, gives the most accurate estimate of the term and expected date of birth. But ultrasound at a later date only confuses in setting such numbers. In the 2nd-3rd trimester, ultrasound should determine the norms or pathologies of fetal development, but not the date of the upcoming birth, because the size of the child, bones, head volumes, chest girths of the baby and the state of the placenta are purely individual indicators and differ from average at times. Someone has a large fetus, so there are errors in the delivery period for 4 weeks in advance, and therefore they resort to unreasonable stimulation of labor, someone has a small child and there are problems with postponing the pregnancy.

Why accuracydefinitions depend on menstruation

Determining the exact date of birth is not an easy question. And it depends on various factors. Any deviation in the well-being of the expectant mother affects the number of days of bearing a child. Considering all the indications of the female body, it is worth noting that the last menstruation still takes into account deviations in the behavior of the whole organism as a whole and therefore serves as an important starting point in setting the timing of pregnancy and the date of birth. A delay or premature onset of menstruation indicates a pathology in the body and therefore helps to take into account all possible options for the development of a future pregnancy. In addition, it is possible to determine the date of birth by the last menstruation most accurately in the absence of the possibility of another diagnosis of a pregnant woman. This is the observation of the interesting situation of a woman in remote villages without the necessary equipment, and when a woman refuses other diagnostics for other reasons (spiritual views, religion, etc.). It should be noted that discrepancies in the estimated date of birth vary within 1-2 weeks. This ensures adequate observation and diagnosis of intrauterine fetal problems.

Approximation of due date

It is always possible to determine the date and date of birth by the last menstruation if a woman remembers these numbers. However, the accuracy will never be 100%. The body of each pregnant woman is purely individual, and the average indicators do not give reason to say that the deadline is set correctly and accurately. About 2 weeks ahead or back should be taken into account when planning the upcoming birth. Well, with an irregularmenstruation and any chronic diseases, discrepancies in dates can be more than 4 weeks.

Another reason for the inaccuracy is that you can find out the due date from your monthly period, if you do not confuse them with menstrual bleeding at 4 weeks of gestation. This happens quite often, especially in women who have given birth to 3 or more children. There is also the possibility of a small placental bleeding, in which the fetus clings to the wall of the uterus. It can also be mistaken for menstruation, which will distort the data on the gestational age, and therefore on the date of the upcoming birth.

Do not forget that inaccuracies can affect the development of the fetus, so it is extremely important to take all the necessary examinations to minimize errors in date calculations.

Feedback on determining the expected date of birth

In discussions on the World Wide Web, there are various reviews about setting the correct date of birth. They are divided into positive and negative.

1. Positive reviews are based on the experience of correctly setting the timing of delivery. In 80%, the date of the expected birth was set by the doctor on the first day of the last menstruation and was calculated using the Negele formula. Differences in numbers were 2-3 days. At the same time, women report that their cycle is constant - 28-30 days. 20% of positive comments from pregnant women are based on setting the date of birth by ovulation, while maintaining at least a 6-month cycle and basal temperature chart. If all factors are calculated correctly, the due dateguessed with an accuracy of 1-2 days.
2. Negative stories of women are most often found in describing the fickle cycle. At the same time, the estimated date of birth is either 3 weeks behind or in a hurry. In this case, there is early or late ovulation or placental bleeding, which is mistaken for menstruation, while it is difficult to accurately determine the gestational age. Often, the incorrect setting of the date of birth in negative reviews is noted when determining the size of the fetus. If the baby is large, the cycle is unstable, etc., the pregnancy is overstayed, and in the end it turns out that neither the woman nor the baby is ready for childbirth. The same problem occurs with a small baby. In this case, later terms of delivery are set, in connection with which the child receives oxygen starvation and infection with the products of his vital activity.

In the end…

Having considered all the possible options for determining the expected date of birth by the last menstruation, it is worth noting that its accuracy depends on many factors:

• constant cycle;
• ovulation;
• somatic condition;
• emotional calm;
• physical activity;
• heredity.

It is worth noting that it is possible and necessary to find out the dates of birth by the last menstruation, since this type of diagnosis is the most common and accurate, based on the experience of obstetricians.

Everyone wants to know when the baby will be born, the date and month of his birth is important for parents. But don't focus on it. Primarilycalculation of the date of the upcoming birth is necessary to control the formation and growth of the fetus, as well as the physical readiness of the pregnant woman for delivery.

Any living organism is very unique. The way and speed of its development depends only on itself. A new person, ready to be born, knows when to do it, since only nature has laid down all possible dates and dates.