Maternal and Perinatal Outcomes of Expectant Management of Full-Term, Low-Risk, Nulliparous Patients

OBJECTIVE To compare risks of maternal and perinatal outcomes by completed week of gestation from 39 weeks in low-risk nulliparous patients undergoing expectant management. METHODS We conducted a secondary analysis of a multicenter randomized trial of elective induction of labor at 39 weeks of gestation compared with expectant management in low-risk nulliparous patients. Participants with nonanomalous neonates, who were randomized to and underwent expectant management and attained 39 0/7 weeks of gestation, were included. Delivery gestation was categorized by completed week: 39 0/7-39 6/7 (39 weeks), 40 0/7-40 6/7 (40 weeks), and 41 0/7-42 2/7 (41-42 weeks) (none delivered after 42 2/7). The coprimary outcomes were cesarean delivery and a perinatal composite (death, respiratory support, 5-minute Apgar score 3 or less, hypoxic ischemic encephalopathy, seizure, sepsis, meconium aspiration syndrome, birth trauma, intracranial or subgaleal hemorrhage, or hypotension requiring vasopressor support). Other outcomes included a maternal composite (blood transfusion, surgical intervention for postpartum hemorrhage, or intensive care unit admission), hypertensive disorders of pregnancy, peripartum infection, and neonatal intermediate or intensive care unit admission. For multivariable analysis, P