No exact prediction for birth dates

Birthdays can only be roughly predicted

08/07/2013

Birthdays can not be accurately predicted, because how long a child stays in the mother's womb is very different. US researchers found that the duration of pregnancies can vary by up to 37 days. It is likely that factors are responsible for the first two weeks after fertilization.

Until just over two weeks ago, Britain was eagerly awaiting the birth of the new heir to the throne. Paparazzi and journalists lined up in front of the hospital weeks before the event, when Duchess Catherine was to give birth to the child. For no one knew when labor would actually begin and the little prince would see the light of day. Whether an accurate prediction about the duration of a pregnancy is possible and which factors influence it has recently been investigated by a research team headed by Anne Marie Jukic of the National Institute of Environmental Health Sciences in Durham. Their results are in the trade magazine „Human Reproduction“ in front.

The researchers used the data from a previous study in which pregnancies had already been studied. Twenty-five women, who were on average 29 years old, gave urine samples every day during the weeks before and after conception, which the researchers used to evaluate hormone levels. From this, the time of ovulation and the day of implantation in the uterus (uterus) were determined. Of course, all children were born - not by caesarean section or by artificial initiation of labor.

Pregnancy duration and birth dates differ up to 37 days
The estimated due date is usually set 280 days after the first day of the last menstrual period. However, the researchers found that the duration of pregnancies can vary by up to 37 days. „The average time from ovulation to birth was 268 days (38 weeks and two days). Even after six premature births were excluded, the duration of pregnancy differed by up to 37 days“, the researchers write. In older women, the pregnancy took longer than younger, it goes on. In addition, the scientists determined that women who were already above average for a long time pregnant, even in the second pregnancy only after the calculated date of birth. The more time between ovulation and implantation of the embryo, the longer the period until birth.

It is very likely that events within the first two weeks after conception have a significant impact on the duration of pregnancy. However, other theories could not be confirmed. „We were unable to confirm any association between pregnancy duration and other factors associated with previous studies, such as body mass index (BMI), alcohol intake, parity, and gender of offspring“, the researchers report in the journal.

Time of birth is said to affect baby's health
According to another study, the time of conception has an impact on the baby's health. Among other things, US researchers at Princeton University came to the conclusion that children who were conceived in May are at an increased risk for premature birth and therefore for certain diseases. Like Janet Currie and Hannes Schwandt in the trade magazine „Influenza viruses could play a role in this, as influenza viruses could cause a premature birth in pregnant women, because the calculated date of birth in May is January or February, and thus the peak flu season in the USA. ag)

Picture: Gemini 2006