HIGH-RISK PREGNANCY SERIES: AN EXPERT’S VIEW We have invited select authorities to present background information on challenging clinical problems and practical information on diagnosis and treatment for use by practitioners. Preterm Premature Rupture of the Membranes Brian M. Mercer, MD Preterm premature rupture of membranes (PROM) af- fects over 120,000 pregnancies annually in the United States and is associated with significant maternal, fetal, and neonatal risk. Management of PROM requires an accurate diagnosis as well as evaluation of the risks and benefits of continued pregnancy or expeditious delivery. An under- standing of gestational age– dependent neonatal morbidity and mortality is important in determining the potential benefits of conservative management of preterm PROM at any gestation. Where possible, the treatment of pregnan- cies complicated by PROM remote from term should be directed towards conserving the pregnancy and reducing perinatal morbidity due to prematurity while monitoring closely for evidence of infection, placental abruption, labor, or fetal compromise due to umbilical cord compression. Current evidence suggests aggressive adjunctive antibiotic therapy to reduce gestational age– dependent and infec- tious infant morbidity. Similarly, review of evaluable data indicates that antenatal corticosteroid administration in this setting enhances neonatal outcome without increasing the risk of perinatal infection. It is not clear that tocolysis in the setting of preterm PROM remote from term reduces infant morbidity. When preterm PROM occurs near term, particularly if fetal pulmonary maturity is evident, the patient is generally best served by expeditious delivery. (Obstet Gynecol 2003;101:178 –93. © 2003 by The Amer- ican College of Obstetricians and Gynecologists.) INTRODUCTION Incidence and Clinical Importance Preterm premature rupture of membranes (PROM) oc- curs in 3% of pregnancies and is responsible for approx- imately one third of all preterm births. Preterm PROM is an important cause of perinatal morbidity and mortality, particularly because it is associated with brief latency from membrane rupture to delivery, perinatal infection, and umbilical cord compression due to oligohydram- nios. Even with conservative management, 50 – 60% of women with preterm PROM remote from term will deliver within 1 week of membrane rupture. Amnionitis (13– 60%) and clinical abruptio placentae (4 –12%) are commonly associated with preterm PROM. The risk of these complications increases with decreasing gestational age at membrane rupture. The frequency and severity of neonatal complications after preterm PROM vary with the gestational age at which rupture and delivery occur, and are increased with perinatal infection, abruptio placentae, and umbili- cal cord compression. Respiratory distress syndrome (RDS) is the most common serious complication after preterm PROM at any gestation. Other serious acute morbidities including necrotizing enterocolitis, intraven- tricular hemorrhage, and sepsis are common with early preterm birth but relatively uncommon near term. Re- mote from term, serious perinatal morbidity that may lead to long-term sequelae or death is common. Figures 1 through 3 present recent gestational age– dependent morbidity and mortality curves from a prospective com- munity-based evaluation of 8523 consecutive women delivering at six hospitals in Shelby County, Tennessee between July 1997 and March 1998. In this evaluation, we found that 33% of live-born and resuscitated infants delivered at 23 weeks survived to discharge from hospi- tal (Figure 1). One-week increments in gestational age were associated with impressive improvements in sur- vival when delivery occurred between 23 and 32 weeks’ From the Department of Obstetrics and Gynecology, MetroHealth Medical Center, Case Western Reserve University, Cleveland, Ohio. Support: The Prematurity Center of The Partnership for Women’s and Children’s Health (University of Tennessee, Memphis; Methodist Healthcare Foundation; LeBonheur Children’s Hospital; and the Tennessee Coordinated Care Network). We would like to thank the following individuals who, in addition to members of our Editorial Board, will serve as referees for this series: Dwight P. Cruikshank, MD, Ronald S. Gibbs, MD, Gary D. V. Hankins, MD, Philip B. Mead, MD, Kenneth L. Noller, MD, Catherine Y. Spong, MD, and Edward E. Wallach, MD. 178 VOL. 101, NO. 1, JANUARY 2003 0029-7844/03/$30.00 © 2003 by The American College of Obstetricians and Gynecologists. Published by Elsevier Science Inc. PII S0029-7844(02)02366-9