Each future mother of the whole nine months is looking forward to meeting with her child and looking for all possible ways of calculating the term of the expected childbirth. Calculating the gestational age is very important for determining the date of delivery. There are many ways to calculate the duration of pregnancy and childbirth: monthly, gynecological examination, chorionic gonadotropin level, and ultrasound examination. We will get acquainted with the main methods of determining the duration of pregnancy and childbirth.
Calculation of pregnancy on monthly and ovulation
To determine the duration of pregnancy and the forthcoming births, the last menstruation uses the formula Negele. For this, from the day of your last menstruation, it is necessary to take three months and add seven days. So, if the first day of the last menstruation was on April 3, the term of the expected delivery will be 10 January. This method of calculating the date of birth is suitable only for those with a regular menstrual cycle and lasts 28 days.
Calculate the gestation period for ovulation is also possible if the woman has a regular menstrual cycle. Thus, with the 28-day menstrual cycle, ovulation occurs on day 14. If a woman accurately remembers the date of unprotected sexual intercourse, then it will not be difficult to calculate the date of birth.
Calculation of the gestational age for the level of chorionic gonadotropin (hCG)
Chorionic gonadotropin is a hormone that rises on the fifth day of pregnancy and can be the first criterion of pregnancy. Every subsequent day, the level of hCG in the blood increases. Normally, the level of chorionic gonadotropin increases by 60-100% every 2 to 3 days. There are special criteria for the growth of chorionic gonadotropin at a certain period of pregnancy. For example, at 1 - 2 weeks of pregnancy, the level of β-HCG is 25 - 156 mU / ml, at 3 - 4 weeks - 1110-31,500 mU / ml, and at 5 weeks it can reach 82,300 mU / ml. Thus, the study of the growth of this hormone, will calculate the duration of pregnancy in the early stages.
Exact calculation of gestational age
Precisely determine the term of the forthcoming birth can be by gynecological examination and ultrasound. When gynecological examination, the size of the uterus is determined, which corresponds to a chicken egg at 4 weeks, and at 8 weeks to a goose. The more experience the doctor-gynecologist, the more accurately he will be able to calculate the duration of pregnancy and expected delivery.
Calculation of pregnancy on ultrasound (ultrasound) is also more informative in the early stages (up to 8 - 12 weeks). After 12 weeks, the size of the fetus depends on the characteristics of its development (peculiarities of blood circulation in the placenta, intrauterine infection, constitutional features of the pregnant woman). After the 20th week of pregnancy, the accuracy of determining the duration of pregnancy progressively decreases. Therefore, if a woman is diagnosed with intrauterine growth retardation in the third trimester, then you should not get upset and sound an alarm, maybe she just has a small fruit.
Calculation of the gestation period for the first fetal movement
Primitives begin to feel the fetus moving from 18 to 20 weeks, and the ones from 15 to 16 weeks old. This is due to the fact that the sensitivity of the future mother, who already once knew the joy of motherhood, is much higher than the one that passes all this for the first time.
We described a variety of possible methods for determining the duration of pregnancy and the expected date of delivery: a calendar, a formula and tables for calculating the gestational age that are used not only by future mothers, but also by their midwives. It should not be forgotten that the date of the specified birth corresponds to 40 weeks of pregnancy, and the normal birth can begin in the period from 37 to 42 weeks.