Any woman who is expecting a baby is keenly interested in how calculate the gestational age, because you need to know this to determine the long-awaited day of the birth of the baby. Unfortunately, no one can accurately set the date of birth, usually they talk about the estimated date. Another point is bewildering in women who are pregnant for the first time - the difference between the period that they themselves determine and the period of pregnancy that the gynecologist will put after the examination. The explanation is quite simple.
Even if a woman knows exactly when there was sexual intercourse, and she had the opportunity to get pregnant, in her attempt to calculate the gestational age a mistake may crept in. After all, fertilization of the egg and the onset of pregnancy can occur only after ovulation - there must be something that can be fertilized. The creature’s sperm are very tenacious and can be in a combat state for several days already in the female body. Therefore, it is rather difficult to say exactly when exactly the conception occurred.
Determining the day of ovulation and thus setting the date of conception is also quite problematic, especially for women who do not have a regular cycle or if their cycle is not monitored at all. This also occurs quite often: young and not very women do not keep a calendar of the onset of menstruation.
To calculate the gestational age, you need to know the exact number when you last started your period. Two hundred eighty days are added to it and the date of birth is received. Where do two hundred eighty days come from? This is ten obstetric months of twenty-eight days - that is how many days a pregnancy should last. Accordingly, it is easy to calculate which week of pregnancy currently.
This is how obstetrician-gynecologists calculate the term and they will definitely ask you when you come to get registered or go to the gynecologist for any reason.
Another way to find out when the birth should take place is to take three months from the date of the last menstruation and add seven days. Let’s say the periods were last time on August 21 minus three months on May 21 plus seven on May 28. This is an indicative date.
By the way, many gynecologists use special calendars that help calculate the exact gestational age, their principle is based on the date when the last menstruation began.
When examining a pregnant woman, an experienced gynecologist can calculate the gestational age, given the change in the size of the uterus. Moreover, the accuracy of this method is high if you come to register before the twelfth week. Another method to set the deadline is an ultrasound scan in the same period, since it is based on measuring the size of the fetal egg.
Why up to twelve weeks? Because in the future an embryo develops and different parents get different children. That is, the size of the child can vary significantly, because babies are born and 2,900 g and 4,300 g.
In the future, it is quite difficult to establish the gestational age, the risk of error increases due to differences in the constitution of mothers and, accordingly, in the development of children. But under observation, the gynecologist performs various measurements that allow you to navigate during pregnancy. In this case, the following are taken into account:
- volume of the abdomen;
- height of the uterine fundus;
- size of the uterus;
- fetal length and head size.
In any case, it should be remembered that the period when he is born is determined by the baby himself, no matter what forecasts mom and doctors make. A normal full-term is a child who appears from the thirty-eighth to the forty-second week. If you are expecting not one, but two or more babies, then the birth is a week earlier.