Your delivery date is calculated from the first day of your last period plus 41 weeks of gestation. A simple calculation ... maybe a little too much! An American study revealed that the term could vary depending on age, birth weight and previous pregnancies.
- You are pregnant and dread not to give birth on the date planned by your gynecologist? If all is well with you and your baby, you do not need to worry unnecessarily while setting the calendar.
- According to the conclusions of an American study published in August 2013 in the journal Human Reproduction, a term pregnancy does not last nine months for all future mothers. By observing the pregnancies of 125 pregnant women, and by making sure to identify the moment when the embryo was implanted by means of urine tests, they found that the average duration of gestation was 268 days, ie 38 weeks and 2 days.
- In total, only 4% of women would give birth after 280 "regulatory" days in the United States (40 weeks after the first day of the last period) and 70% within 10 days of the expected date. But how to explain these variations?
A variable duration according to the age and the birth weight of the mother
When a pregnancy is going well, three main factors may explain that it does not last nine months "pile":
- The age of the mother. Older women have longer pregnancies than others. The study estimates that each additional year adds on average one day of pregnancy.
- The birth weight of the mother. Women who weighed at birth 100g more than the average weight had a pregnancy lengthened by one day compared to the average.
- The number of pregnancies. From the 2nd child, add 2.5 days of additional pregnancy. So, if you're expecting your 3rd child, add 5 more days than your eldest term ...
- Although researchers of the National Institute of Environmental Health Sciences, the source of these results, believe that it is premature to draw scientific conclusions, they invite the medical profession to take into account this notion of individual variability especially when deciding to to start a childbirth ...