As each pregnancy is unique and subjective, the length of healthy pregnancies can vary naturally between different women. Some of this variation was assumed that it was caused by errors in determining the exact date of conception leading to the wrong age of the fetus.
A written by the NIH, National Institute of Environmental Health, which was published by Oxford University Press in 2013, study establishes that pregnancies may vary up to 5 weeks. The study included 125 women in the consideration of the early 1980s, they were trying to conceive and had no fertility problem. They did this by using measurements of hormone urine to pinpoint the exact date of ovulation and embryo implantation
The study did not include :.
1. The estimated gestational age by last menstrual period or ultrasound, as it can lead to both imperfect measures.
2. Pregnancies were artificially shortened by induction of labor, cesarean deliveries.
The results of the study showed that the median gestational age (ovulation to birth) was 268 days (ie 38 weeks and 2 days). After excluding 6 premature deliveries, the range of length of gestation was still 37 days. Even with these accurate data conceptions day, there were still variations on the due date
The study also found various gestation periods in these scenarios :.
1. Conceptions that took longer implant.
2. Pregnancies with a rapid increase in progesterone (sex hormone that is released during the menstrual cycle, embryo formation and pregnancy).
3. older mothers
4. Mothers who previously had long pregnancies
5. Mothers who were heavier during his own birth.
They found no correlation between the longest pregnancy and BMI, the baby’s sex and alcohol intake.
The study does not provide information really unknown as it was already demonstrated that only 4 percent of women give birth on the due date, which is usually 280 days after the last menstrual period. Again, this just goes to show that doctors and midwives should not put too much emphasis on a date particular maturity rather inform patients about changes and provide a couple of possible dates could expect the arrival of their baby.