Scientists have found that the length of time a woman gets pregnant can vary by as much as five weeks. Although it has long been known that human gestation typically lasts between 37 and 42 weeks. But the reason for the discrepancy has previously been explained as flaws in the methodology for estimating maturities.
The British \”Independent\” website reported on August 7 that according to calculations, a woman\’s expected date of delivery is the 280th day after the start of her last menstrual period, which is considered the best calculation method. But only 4% of women give birth on the day of their due date, while 70% give birth within 10 days before or after the due date.
However, researchers at the National Institute of Environmental Health Sciences were able to determine when a woman became pregnant by taking daily urine samples. This allowed them to isolate the role of natural variation in determining the length of pregnancy.
Among 125 women, they found that the average time from ovulation to delivery was 268 days, or 38 weeks and 2 days. The findings, published in the journal Human Reproduction, suggest the length of a woman\’s gestation period may vary by as much as 37 days.
\”We were a little surprised by this finding,\” said Dr. Anne-Marie Yukik, a postdoctoral researcher in epidemiology at the National Institute of Environmental Health Sciences. \”We knew women differed in how long they were pregnant, but part of the reason was that this difference had been explained by gestational age. Calculation Errors In this study, we took care to exclude the above sources of error when measuring gestation length, but we still found differences in women\’s gestation times by 5 weeks, which is really interesting.
According to reports, the length of a woman\’s pregnancy will be affected by a series of factors. Older women tend to have children later in life, and heavier women take longer to get pregnant.
The Royal College of Midwives said the research reiterated professionals\’ experience that \”every woman is different\” and called on healthcare practitioners to exercise caution when intervening in women early in pregnancy. But they think it\’s still useful to calculate your due date.
Melvey Jokinen, professional advisor on practice and standards at the Royal College of Midwives, said: \”I don\’t think this means that our college and other doctors will stop calculating pregnant women\’s due dates. What we should be explaining to women is that due dates are always estimates. As this study shows As our experience shows, the timing of pregnancy varies from person to person.\”