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Lucky arithmetic: how the gestational age is considered
“I will have a baby!” – this good news raises many questions for the expectant mother. And the first of them concerns the due date. It is not easy to calculate it because it is difficult to determine the date of conception. But there are several ways, proven by centuries of experience and science.
How is the gestational age considered?
How to correctly calculate the gestational age?
Before birth, the baby is in the mother’s womb for 38 weeks. But human biology is so complex that it does not fit into a strict framework. A woman can make a mistake in determining the date of birth, even if she remembers exactly the day of conception. Sperm are able to remain in the fallopian tubes for several days, maintaining their activity.
But even in the old days, midwives knew how to calculate the cherished dates. Here are the methods that obstetricians still use today:
- Remember on what day your last period began. Count off 9 months from this date on the calendar. Add a week.
- Take the first day of your last period as a starting point. Add 280 calendar days to it.
- Count from the day of ovulation. It occurs 2 weeks after the first day of the last menstruation. Count 38 weeks from the date of ovulation.
- Remember the number when you first felt the fetal movement in your abdomen. If you are expecting your first child, add 20 weeks to this date. In subsequent pregnancies, add 14 days more.
These methods are only suitable for women with a perfect cycle. Hormonal disruptions, as well as chronic diseases can bring forward or postpone the date of birth.
How to count pregnancy by month?
The antenatal clinic patients are often perplexed – why does the doctor write down “22 weeks” if the 4th month will end soon? The fact is that obstetricians do not count the first 7 days. The countdown starts from the 2nd week – it will be the first for your doctor. There is also a difference in months. If you look at the calendar, you will see that most months are 4 weeks long and 2-3 days long. In gynecology, lunar months are used – exactly 28 days each.
How do you calculate your due date? It depends on from what moment the gestational age is considered. From the first day of the last menstruation – 40 weeks, and from the day of ovulation – 38 weeks. The calculation is carried out according to the lunar calendar – 10 months by 28 days. In the usual chronology, it turns out to be a little over 39 weeks.
Knowing how experienced women consider the gestational age, one should not neglect the achievements of science. An ultrasound study carried out before the 12th week will determine the date of birth with an accuracy of the day.
Obstetrician-gynecologist of the network of centers of reproduction and genetics “Nova Clinic”.
To determine the date of birth, the doctor may be guided by the data on the menstrual cycle or the results of the first ultrasound. So, if a woman has a regular menstrual cycle, then the date of birth is determined by the first day of the last menstruation. If the cycle is irregular, then according to the first ultrasound examination.