Maternal sleep duration and neonate birth weight: A population-based cohort study.

Objective Sleep duration is an important health indicator. Our aim was to investigate the association between maternal sleep duration and infant birthweight. Methods The study included 2,536 mother-infant pairs of a Spanish birth cohort (2004-2006, INMA project). The exposures were questionnaire-based measures of sleep duration before and during pregnancy. The primary outcome was infant birthweight score (g) standardized to 40 weeks of gestation. Results In women sleeping less than 7 hours per day before pregnancy, each additional hour of sleep increased birthweight score by 44.7 g (p = 0.049) in the minimally-adjusted model, although findings were not statistically significant after consid…