• TitaAlan T NATNDepartments of Obstetrics and Gynecology, University of Alabama at Birmingham, Birmingham, Alabama, Northwestern University, Chicago, Illinois, University of Utah Health Sciences Center, Salt Lake City, Utah, Stanford University, Stanford, , Lindsay Doherty, William A Grobman, Uma M Reddy, Robert M Silver, Gail Mallett, Madeline Murguia Rice, Yasser Y El-Sayed, Ronald J Wapner, Dwight J Rouse, George R Saade, John M Thorp, Suneet P Chauhan, Maged M Costantine, Edward K Chien, Brian M Casey, Sindhu K Srinivas, Geeta K Swamy, Hyagriv N Simhan, George A Macones, and Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Maternal-Fetal Medicine Units (MFMU) Network.
• Departments of Obstetrics and Gynecology, University of Alabama at Birmingham, Birmingham, Alabama, Northwestern University, Chicago, Illinois, University of Utah Health Sciences Center, Salt Lake City, Utah, Stanford University, Stanford, California, Columbia University, New York, New York, Brown University, Providence, Rhode Island, University of Texas Medical Branch, Galveston, Texas, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, University of Texas Health Science Center at Houston-Children's Memorial Hermann Hospital, Houston, Texas, The Ohio State University, Columbus, Ohio, Metro Health Medical Center-Case Western Reserve University, Cleveland, Ohio, University of Texas Southwestern Medical Center, Dallas, Texas; University of Pennsylvania, Philadelphia, Pennsylvania, Duke University, Durham, North Carolina, University of Pittsburgh, Pittsburgh, Pennsylvania, Washington University in St. Louis, St. Louis, Missouri; the George Washington University Biostatistics Center, Washington, DC; and the Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland.
• Obstet Gynecol. 2021 Feb 1; 137 (2): 250-257.

ObjectiveTo compare risks of maternal and perinatal outcomes by completed week of gestation from 39 weeks in low-risk nulliparous patients undergoing expectant management.MethodsWe 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<.0125 was considered to indicate statistical significance for the coprimary outcomes.ResultsOf 2,502 participants who underwent expectant management, 964 (38.5%) delivered at 39 weeks of gestation, 1,111 (44.4%) at 40 weeks, and 427 (17.1%) at 41-42 weeks. The prevalence of medically indicated delivery was 37.9% overall and increased from 23.8% at 39 weeks of gestation to 80.3% at 41-42 weeks. The frequency of cesarean delivery (17.3%, 22.0%, 37.5%; P<.001) and the perinatal composite (5.1%, 5.9%, 8.2%; P=.03) increased with 39, 40, and 41-42 weeks of gestation, respectively, and hypertensive disorders of pregnancy decreased (16.4%, 12.1%, 10.8%, P=.001). The adjusted relative risk, 95% CI (39 weeks as referent) was significant for cesarean delivery at 41-42 weeks of gestation (1.93, 1.61-2.32) and for hypertensive disorders of pregnancy at 40 weeks (0.71, 0.58-0.88) and 41-42 weeks (0.61, 0.45-0.82). None of the other outcomes were significant.ConclusionIn expectantly managed low-risk nulliparous participants, the frequency of medically indicated induction of labor, and the risks of cesarean delivery but not the perinatal composite outcome, increased significantly from 39 to 42 weeks of gestation.Copyright © 2021 by the American College of Obstetricians and Gynecologists. Published by Wolters Kluwer Health, Inc. All rights reserved.

10 keywords...

hide…