Date of delivery: how to calculate it?: Your doctor will usually calculate the expected date of delivery for you. This being said, to know the time long-awaited as quickly as possible, you can also calculate it yourself … The point in this article.
Calculating the date of delivery from the time of the onset of pregnancy
The time of onset of pregnancy (DDG) corresponds to the day on which the egg was fertilized by the spermatozoon. It is possible that you know this day, especially if you have very regular menstrual cycles and you know your ovulation date.
In this case, it takes only 266 days from the DDG to know your expected delivery date. If necessary, the doctor can also determine the DDG with enough precision thanks to the evolution of the fetus (visible on the ultrasound).
Calculate the delivery date from the start date of the last menstrual period
This is the most used method of calculation, as most women know more quickly the day of their last menstruation than that of fertilization.
To calculate the delivery date, the principle is to add 287 days to the start date of your last menstruation. These 287 days correspond to 41 weeks of amenorrhoea (SA), which is considered the average term of pregnancy in France (note that in Belgium, the calculation is rather done from 40 SA).
Another method, easier to make the head (or before a calendar): subtract three months from the start date of your last rules (DDR) and then add 14 days to find the term of 41 SA.
Concrete example: your DDR is June 20 of the current year. By subtracting three months, you get the date of March 20th. By adding 14 days, you get the expected time of delivery: April 3 of the following year.
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A date of theoretical birth
Whatever the method used, the date obtained is only theoretical even if it is provided to you by your doctor. Indeed, many factors can influence the time of delivery, such as the number of previous pregnancies, for example (second pregnancies last one week less than the first pregnancies).
In reality, many children are not born after nine full months of pregnancy, but from one to a few weeks earlier. This leaves you ample time to prepare yourself to give birth without pain … The baby can also be born in perfect health a little after the expected date. To avoid complications. However, it is frequent to initiate delivery after 42 weeks.
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