['The purpose of this study was to examine the associations of sleep disturbances during pregnancy with cesarean delivery and preterm birth.', "In this prospective study, 688 healthy women with singleton pregnancy were selected from three hospitals in Chengdu, China 2013-2014. Self-report questionnaires, including the sleep quantity and quality as well as exercise habits in a recent month were administered at 12-16, 24-28, and 32-36 weeks' gestation. Data on type of delivery, gestational age, and the neonates' weight were recorded after delivery. After controlling the potential confounders, a serial of multi-factor logistic regression models were performed to evaluate whether sleep quality and quantity were associated with cesarean delivery and preterm birth.", 'There were 382 (55.5%) women who had cesarean deliveries and 32 (4.7%) who delivered preterm. Women with poor sleep quality during the first (OR: 1.87, 95% CI [1.02-3.43]), second (5.19 [2.25-11.97]), and third trimester (1.82 [1.18-2.80]) were at high risk of cesarean delivery. Women with poor sleep quality during the second (5.35 [2.10-13.63]) and third trimester (3.01 [1.26-7.19]) as well as short sleep time (<7\u2009h) during the third trimester (4.67 [1.24-17.50]) were at high risk of preterm birth.'] Are sleep disturbances during pregnancy associated with cesarean delivery and preterm birth?