Duration of pregnancy:
A pregnancy theoretically lasts 9 months. But in reality, the normal duration of pregnancy is a bit complicated and varies from woman to woman.
The duration of gestation varies according to the studies between 280 and 290 days from the first day of the date of the last menstrual period (that for regular cycles of 28 days), that is to say 40 + 0 to 41 + 3 SA (41 weeks of amenorrhea + 3 days).
The information to remember for future mothers: a term pregnancy is a delivery between 37 SA + 0 and 41 SA + 5 (41 SA + 5 days).
How to determine the age of the fetus?
* To estimate the progress of your pregnancy, there are two main methods: the calculation of the week of pregnancy or the calculation of the week of amenorrhea. Per week of pregnancy, we mean "effective pregnancy week": in other words, the calculation starts from the day of fertilization. For their part, weeks of amenorrhea count the number of weeks without menstruation, so since the day of the beginning of your last period.
* This difference between the calculation methods results in a lag of two weeks in the result obtained. In total, a "normal" pregnancy of 9 months is equivalent to 39 weeks of pregnancy or 41 weeks of amenorrhea. Practical data to determine your delivery date.
* F.Y.I, doctors rather use the calculation in weeks of amenorrhea.
* How to calculate your pregnancy week
To calculate your actual pregnancy week, it is enough to count the weeks passed since the supposed day of the fertilization. It remains to be determined ... If you have very regular cycles of 28 days, your ovulation normally takes place on the 14th day after the start of your period. Your fertility period then extends between the 10th day and the 15th day of the cycle (four days before ovulation and one day after).
* You can refine the result depending on the date of your intercourse, but in practice, determining the exact date of fertilization is impossible for most women because they do not know the day of their ovulation. That's why doctors usually prefer to calculate weeks of amenorrhea: just count the weeks since the start date of your last period. This date is much easier to know than your ovulation date.
The dating ultrasound
* If the pregnancy week is not easy to calculate oneself, it is easy to determine thanks to the dating ultrasound. Taking place between the 11th and 13th weeks of amenorrhea, it gives an accurate estimate of the baby's age according to his level of development. You will know which week of pregnancy you really are.