The lengths of women’s pregnancies may vary by as much as 5 weeks, and events very early in pregnancy may influence the length of gestation, according to a recent study.
The study provides the most reliable measurements of human gestation to date and offers new insights into some factors that may influence when a women delivers. Anne Marie Z. Jukic, PhD, a postdoctoral fellow at the National Institute of Environmental Health Sciences, and her colleagues determined the lengths of 125 pregnancies of women who participated in the Early Pregnancy Study, a prospective cohort study conducted between 1982 and 1985. The women provided daily urines from the time they discontinued using birth control through early pregnancy, which allowed the scientists to determine the day they ovulated based on hormones in the urine. Jukic and colleagues also collected follow-up information from the women.
Kuehn BM. Pregnancy Length May Vary by 5 Weeks. JAMA. 2013;310(9):893. doi:10.1001/jama.2013.277342