Placental abruption, the premature detachment of the placenta, before birth and after 20 weeks gestation, occurs in 0.6% -1% of all pregnancies in the United States. Little is known about the duration of labor or the risk of neonatal morbidities attributed to abruption. This study examined labor duration, delivery mode, and neonatal outcomes associated with placental abruption among singleton pregnancies in the Consortium on Safe Labor study (n=223,252), a retrospective, observational study of deliveries from 2002-2008 in 19 U.S. hospitals. Models were fit using generalized estimating equations controlling for maternal age, race, pre-pregnancy BMI, insurance, history of cesarean, marital status, and study site (cervical dilation, birthweight, and gestational age were also included for labor and delivery analyses). Labor duration was modeled for each of the three stages and calculated separately by parity (nulliparous or multiparous) and labor type (induced or spontaneous).

Abruption was associated with elevated risk of cesarean delivery among both nulliparous (RR=1.67, 99% CI: 1.54, 1.80) and multiparous women (RR=1.49, 99% CI: 1.38, 1.59). Abruption was not associated with differences in stage 1 or stage 2 labor in any group, but was associated with a shorter duration of stage 3 labor among multiparous women with spontaneous labor ((exp) β = 0.9, 99% CI: 0.8, 0.9) that was not clinically meaningful (1 minute). Abruption was associated with elevated risk of neonatal interventions including newborn resuscitation (RR=1.54, 99% CI: 1.48, 1.61) and longer Neonatal Intensive Care Unit Length of Stay (NICU LOS) (IRR=1.98, 99% CI: 1.83, 2.14), as well as morbidities and mortality including respiratory distress syndrome (RR= 7.40, 99% CI: 6.77, 8.04), apnea (RR=6.63, 99% CI: 5.86, 7.40), asphyxia (RR=8.96, 99% CI: 6.06, 11.85) and perinatal death (RR=7.29, 99% CI: 5.87, 8.70). With the exception of NICU LOS among term and non-low birthweight neonates, all associations remained significant regardless of the timing of abruption, gestational age, birthweight, or delivery mode.

Contrary to prior studies, abruption was not associated with shorter duration of labor. Abruption was associated with increased morbidity among surviving neonates, which adds to the burgeoning literature highlighting the importance of placental functioning on health during infancy.