Steps forward to establish the equation useful for calculating the exact duration of a pregnancy: American researchers have in fact found that the times of gestation vary for each woman and depend on some events of the first few weeks from conception such as the levels of certain hormones and the time necessary for the embryo to implant itself in the uterus.
The discovery comes thanks to the work conducted by Anne Marie Jukic of the National Institute of Environmental Health Sciences (Durham), who for the first time followed 125 spontaneous pregnancies from start to finish, observing step by step the nine months, from ovulation to conception. at childbirth.
READ MORE WHAT WEEK ARE YOU AT AND SUBSCRIBE TO PREGNANCY GUIDE
The study appeared in Human Reproduction. Current clinical practice assigns the 'due date' (the presumed day of delivery) 280 days after the start of the last menstruation, but only 4% of women give birth at 280 days.
The researchers found that pregnancy lasts an average of 268 days from ovulation with a woman-to-woman variability of five weeks, which cannot be explained, as previously believed, with the error in the estimate of the gestational age, but which is instead attributable to natural events relating above all to the first two weeks of the embryo's life.
The experts followed day after day the women who, intending to conceive a baby naturally, took a urine test every morning.
In this way, the researchers dated exactly the day of ovulation and then the day of conception. Then with ultrasound and hormonal dosages they also traced the moment of implantation in the uterus.
Following the women until delivery, it emerged that the pregnancy lasts an average of 268 days from ovulation and that there is an individual variability of five weeks depending on various factors: for example, if the embryo takes longer to implant, the pregnancy lasts for more. Initial progesterone levels as well as the age and weight of the pregnant woman also affect.
CALCULATE THE EXPECTED DATE OF BIRTH ONLINE
IN THE FORUM FUTURE MOMS TALK ABOUT PREGNANCY
TAG:
- pregnancy planner
- weeks of pregnancy
- weeks 1-13
