ABSTRACT: Counseling and management of women at risk for delivering during the periviable period (200/7 through 256/7 weeks) is challenging because difficult decisions must be made in emotional circumstances. This report summarizes a 2013 workshop held at the annual meeting of the Society for Maternal-Fetal Medicine. The authors review the benefits and risks of obstetric and neonatal interventions related to periviable birth, outline counseling measures, describe newborn outcomes, and discuss research-education factors for treating these patients.
About 0.4% to 0.5% of all births occur at 27 weeks’ gestation or less and account for more than 40% of infant deaths and most neonatal deaths. Infants born at 20 and 21 weeks do not survive, despite resuscitation efforts. Survival rates for births at 22, 23, 24, and 25 weeks’ gestation are 6%, 26%, 55%, and 72%, respectively.
All periviable births should occur in tertiary care centers with experts in maternal-fetal medicine and the availability of highest levels of neonatal intensive care unit service. Obstetric interventions for periviable gestations include emergent cerclage, tocolytic therapy, antibiotics for group B streptococcus prophylaxis or to reduce infection and prolong latency after preterm premature rupture of the membranes, antenatal corticosteroids to enhance fetal maturation, and a willingness to intervene to prevent stillbirth or fetal trauma at delivery. Tocolytic therapy reduces uterine activity and allows time for antenatal corticosteroid effects, but data do not demonstrate pregnancy prolongation for more than 24 to 48 hours or newborn benefits. Cerclage, performed at an average 22 weeks’ gestation, can prolong pregnancy 7 to 9 weeks compared with 2 to 3 weeks for not undergoing cerclage and with increased live birth and neonatal survival. Corticosteroid administration is one of the most effective antenatal interventions to improve infant outcomes. Data from an observational cohort found that death or neurodevelopmental impairment at 18 to 22 months was lower for infants exposed to antenatal corticosteroids and born at 23 weeks (83.4% vs 90.5%; adjusted odds ratio [aOR], 0.58; 95% confidence interval [CI], 0.42–0.80), at 24 weeks (68.4% vs 80.3%; aOR, 0.62; 95% CI, 0.49–0.78), and at 25 weeks (52.7% vs 67.9%; aOR, 0.61; 95% CI, 0.50–0.74), but not at 22 weeks (90.2% vs 93.1%; aOR, 0.80; 95% CI, 0.29–2.21). Death, intraventricular hemorrhage, or periventricular leukomalacia and death or necrotizing enterocolitis were also significantly less frequent among infants born at 23, 24, and 25 weeks. The benefits regarding reduced death rates persisted through 18 to 22 months (OR, 0.59; 95% CI, 0.53–0.65) for infants born at 22 to 25 weeks. Infants exposed to antenatal corticosteroids before birth at 24 to 25 weeks had less frequent respiratory distress syndrome (OR, 0.77; 95% CI, 0.60–0.98), less frequent severe intraventricular hemorrhage (OR, 0.49; 95% CI, 0.36–0.67), and lower mortality (OR, 0.65; 95% CI, 0.5–0.86) compared with unexposed infants. For infants born at 22 to 23 weeks, antenatal corticosteroid exposure decreased mortality rates (OR, 0.72; 95% CI, 0.53–0.97). Magnesium sulfate treatment reduced cerebral palsy (relative risk [RR], 0.68; 95% CI, 0.54–0.87) and gross motor dysfunction (RR, 0.61; 95% CI, 0.44–0.85) among survivors without increasing mortality (RR, 1.04; 95% CI, 0.92–1.17). Intrapartum antibiotic prophylaxis against group B streptococcus reduced newborn infection, and antibiotic treatment during conservative management of preterm premature rupture of the membranes prolonged pregnancy and reduced newborn infections.
The next decision concerns mode of delivery. Current data do not consistently support routine cesarean delivery to improve perinatal mortality or neurologic outcomes for early preterm infants. Cesarean delivery in the periviable period also incurs greater maternal morbidity, both immediately postoperatively and for future pregnancies.
A team approach to counseling is required for women at 20 weeks’ gestation or greater. Guidance for perinatal management of anticipated or imminent periviable birth should be offered based on the likelihood of infant survival and long-term morbidities. Infants born at 21 weeks or less do not survive regardless of aggressive intervention. Most infants born at 24 weeks or greater survive if liveborn and resuscitated, but most liveborn, resuscitated infants born at 22 to 23 weeks will not survive. With delivery at less than 22 weeks, interventions that increase maternal morbidities should be avoided, and liveborn infants should be offered comfort care. Because most newborns at 24 to 25 weeks will survive if resuscitated, efforts to prolong pregnancy, intrapartum interventions for fetal benefit, and neonatal resuscitation should be offered. At 22 to 23 weeks, decisions are based on whether the fetus is considered potentially viable.
Elements of successful stabilization include a preresuscitation checklist for equipment function, clearly assigned responsibilities for personnel, and adherence to the Neonatal Resuscitation Program algorithm. If effective pulmonary ventilation is established, cardiopulmonary resuscitation is rarely needed. Hypothermia is a major threat to the survival of periviable newborns. The delivery room should be 25°C (77°F) or greater to prevent hypothermia, but even if it is prevented, many periviable infants become hypothermic during transfer to the neonatal intensive care unit. Critical to continued survival are respiratory and cardiovascular support; fluid, electrolyte, and nutritional management; treatment of acid-base imbalances; and use of cerebral protection measures.
Goals of counseling are to provide objective information in a compassionate manner, permit shared decision making, and support the family. Critical components vary depending on whether it is done before birth, after birth, or both; the likelihood of survival; and the likelihood of long-term disability. Discussions can include the benefits/risks of obstetric interventions, utility and timing of transfer to a tertiary care obstetric and neonatal facility, alternatives to and rationale for or against active maternal and neonatal intervention, and options for redirecting or withdrawing life-sustaining interventions. Precise predictive models based on ascertainable, updated, and accurate measures are needed.