Working Night Shift, but Not Heavy Lifting, Is Risk Factor for Preterm Birth

From MedPage Today:

Pregnant women who work the graveyard shift face a significantly higher risk of preterm delivery, yet long hours, standing all day, and heavy lifting were not risk factors, investigators here reported.

Working between 10 p.m. and 7 a.m. during the first trimester raised the risk by at least 50% (relative risk 1.5, 95% confidence interval 1.0-2.0), according to Lisa A. Pompeii, Ph.D., of the University of Texas School of Public Health here.