Sleep patterns in late pregnancy and risk of preterm birth and fetal growth restriction.

Background: During pregnancy, women are at particular risk for sleep deprivation and snoring because of the physiologic and hormonal changes of pregnancy. There is limited evidence for the association between sleep patterns in pregnancy and adverse birth outcomes. We examined the association of sleep duration and snoring in late pregnancy with the risk of preterm birth and fetal growth restriction.

Methods: We used data from the prospective mother-child cohort "Rhea" study in Crete, Greece 2007-2009. The analysis included 1091 women with singleton pregnancies, providing complete data on sleeping habits at the third trimester of gestation and birth outcomes. Fetal growth restriction was based on a customized model, and multivariate log-binomial regression models were used to adjust for confounders.

Results: Women with severe snoring were at high risk for low birth weight (relative risk = 2.6 [95% confidence interval = 1.2-5.4]), and fetal-growth-restricted neonates (2.0 [1.0-3.9]) after adjusting for maternal age, education, smoking during pregnancy, and prepregnancy body mass index (BMI). Women with sleep deprivation (≤5 hours sleep) were at high risk for preterm births (1.7 [1.1-2.8]), with the highest risk observed for medically indicated preterm births (2.4 [1.0-6.4]) after adjusting for maternal age, education, parity, smoking during pregnancy, and prepregnancy BMI.

Conclusions: These findings suggest that women with severe snoring in late pregnancy have a higher risk for fetal-growth-restricted neonates; and women with sleep deprivation have a higher risk for preterm births. The mechanisms underlying these associations remain unclear.