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How to count weeks during pregnancy: how do doctors calculate the term
When will the baby be born? Is his intrauterine development going correctly, why does the ultrasound, the doctor and the expectant mother differ in the calculation of the weeks of pregnancy? And, in general, how to count weeks during pregnancy? These questions often plague women who are preparing to become mothers for the first time. Let’s figure it out.
How to count weeks during pregnancy correctly?
We are used to hearing “9 months”, “a month before giving birth,” “in the seventh month of pregnancy,” etc. But doctors consider the gestational age on a weekly basis. Why?
In fact, an average of 266 days pass from the day of conception to childbirth, which is 38 weeks. About two weeks after the date of the onset of menstruation, ovulation occurs – the release of a mature egg into the fallopian tube. If a sperm manages to intercept it on the way, conception occurs. However, only the mother herself can know the exact date of conception, and even then it is most often difficult.
How do doctors count the weeks of pregnancy? The obstetric period is calculated from the first day of the last menstruation. Before the expected date of birth, 280 days on average pass from the last critical days, which is equal to 40 weeks. Therefore, according to the obstetric term, the fetus is always 2 weeks older than its embryonic age.
Counting in weeks is much more convenient than in months, because each week is a certain stage in the development of the baby.
Trimesters – what are they?
Conventionally, pregnancy is divided into 3 parts – the so-called trimesters. The duration of each of them is 13 weeks. Why is this division necessary, if it is already known how the weeks of pregnancy are counted? This is done for the convenience of observing the development of the fetus.
1. The very first trimester is the most important stage in the development of a future baby. It was at this time that the laying and formation of not only its sex, but also internal organs, nervous system and even teeth took place! But it is the first trimester – and the most alarming time, miscarriages and complications lie in wait for the expectant mother. 2-3 and 8-12 weeks are considered critical; if they go well, then the chance of carrying a baby and having him healthy is close to 90%.
2. The second trimester is from the 14th to the 27th week, and the weeks from the 18th to the 22nd are critical here. In general, this is the quietest period of bearing crumbs, mother is still full of strength, and the upcoming motherhood is full of joys: the first movements, the growth of the tummy, the opportunity to find out who lives inside – a son or a daughter.
3. Third trimester – from the 28th to the 40th week. This is a time of intensive growth of the baby, and here it is important to avoid situations that provoke premature birth. Although modern neonatology is already quite coping with nursing babies born even at the beginning of the last trimester.
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