How to calculate the term of delivery: several ways

Let's talk about what methods exist for calculating the expected date of delivery.

At the moment when the woman finds out thatpregnant, she immediately has the question: "When will the baby be born?" Modern medicine offers several basic ways with which doctors have the opportunity to determine the date when it is supposed to happen.

how to calculate the term of childbirth
How to calculate the term of birth by obstetrical method

The most popular and often used methodcalculation - from the date when there was a last menstrual bleeding, or the formula of Negele. Special calendars for midwives are compiled on it, and the term of birth for this reason is called "obstetric".

The calculation is made from the very first day when the last menstruation began, it departs for three months and seven more days are added. That is, by the first day there are exactly forty weeks.

This option is the most popular, but notquite accurate. In addition, most women know when the conception occurred, and they determine the date of delivery by the date of conception, and therefore they are very surprised when the timing is divergent.

How to calculate the term of birth in an embryonic way

By embryonic is meant the duration of pregnancy bythe calendar, which is made on the day of ovulation. It is considered to be the most optimal time for conception, therefore this date is the starting point.

how to calculate the term of childbirth
If your cycle lasts twenty-eight days, thenovulation occurs on the fourteenth. If it is shorter or, conversely, longer, it is determined by specially designed tables, because according to calculations, ovulation can occur on different days.

How to calculate the term of delivery for the first visit to the gynecologist

During the very first visit to a specialistthe doctor-midwife will be examined, eventually making conclusions about the expected date of birth. This conclusion is based on the following indicators:

  • the size of the uterus;
  • height of its bottom;
  • the size of the abdomen;
  • size of the fetus.

The sooner the expectant mother comes to consult a doctor, the more accurately the date of birth will be determined.

How to calculate the term of delivery based on the results of ultrasound

how to calculate the term of childbirth
To date, this method is considered the most accurate among all others, it is only necessary to take into account the timing when the study was conducted.
At the first screening after receiving its results, the expected date of delivery can be determined with an accuracy of 2-4 days.

During the first trimester, that is, the first12 weeks, between the sizes of the embryo there are no special differences. But, when the second and especially the third trimester begins, the differences in weight and fetal growth can be significant. Therefore, the estimated date of delivery at such times is almost impossible to determine with accuracy.

For an approximate calculation of the term of labor there isa large number of ways. In addition, there is a lot to take and about the sex of the unborn child. There are so many different interesting tables with which you can calculate the sex of the child by the month of conception and the age of the parents at that time.