When a woman enters a state of pregnancy, innumerable unknowns appear in everything that happens. The one that stands out the most is the sex of the baby and among other questions is how many weeks or days she has been pregnant. For this, we will analyze how to count the weeks of pregnancy, doing a review from the last day of menstruation.
The fact that the weeks are counted makes sense, since it would be difficult to calculate the days because each woman ovulates differently. There are only 15% of women who have a cycle of exactly 28 days, since, if we rebound to this data, we would have a much greater success than pregnancy time.
How do you count the exact date of pregnancy?
If a woman has an accurate estimate of when she has been ovulating and has had sexual intercourse, there would be no problem in offer the precise data of when she became pregnant. But these data are not accurate, since the woman may be very active on those days and conception has occurred on a day other than ovulation.
However, an approximation is calculated or made thanks on the first day of menstruation. From here, the weeks of pregnancy, the trimesters and the probable date of delivery begin to be counted.
How are weeks of pregnancy counted
As we have reviewed, it is based scoring the first day of menstruation. From here, 7 days are added and it is not taken into account if there was sexual intercourse. The calculation is made from here, since it is easier to establish the exact moment of fertilization of the ovum together with an onset of pregnancy that may coincide until 7 days after intercourse.
Calculate gestational age
The duration of pregnancy lasts 40 weeks, although it can be shortened or exceeded until week 41.
First term:
1 month – up to 4 and a half weeks of gestation.
2 months – from 4 and a half weeks to 9 weeks.
3 months – from 10 to 13 and a half weeks.
Second quarter:
4 months – from 13 and a half weeks to 18 weeks.
5 months – from 19 to 22 weeks of gestation.
6 months – from 23 to 27 weeks.
Third trimester:
7 months – from 28 to 31 weeks.
8 months – from 32 to 36 weeks.
9 months – from 37 to 42 weeks.
There are several differences: the weeks of pregnancy They are counted from the end of the last period until the time of delivery (approximately 40 weeks). is not the same as the weeks of gestation, where does it start from when the pregnancy has been gestated. It is calculated by counting two weeks after the last period, on the same days where fertilization coincides.
Gestogram to calculate the probable date of delivery
Other ways to calculate the weeks of pregnancy
If it has not been possible to give precise information on the gestational age of the future baby, there are other alternatives that can diagnose the weeks of pregnancy. routine ultrasound It can clarify a lot of the data. Measurements are made to the baby so that the data can be confirmed.
Another alternative would be to do a measurement of the height of the uterus. The distance between one of the pelvic joints and the uterine fundus is measured. From here, some mathematical calculations are made that will approximate the time of gestation.
Analysis of the amount of Beta hGC in blood (chorionic gonadotropin) this hormone is released by the embryo in its implantation in the maternal uterus and will help to give an accurate date of pregnancy.
Some facts to keep in mind is that 40 weeks actually corresponds to 38 weeks of fetal development. With this information, it is completely normal that the delivery it comes to advance 15 days or delay up to 7 days. Another way to calculate childbirth is by calculating 9 months plus one week, from the date of the last menstruation.