Predicting survival of periviable fetuses using NICHD fetal heart rate categories

OBJECTIVE: To evaluate whether National Institute of Child Health and Human Health and Development (NICHD) fetal heart rate categories were predictive of neonatal survival in periviable pregnancies. METHODS: We reviewed the charts of 57 infants delivered at 23 and 24 weeks' gestation. Fetal heart rate tracings were evaluated following the NICHD 2008 criteria, using the acceleration height of 10 bpm and duration of 10 s. Multiple logistic regression analyses were performed using survival, fetal morbidities, and cord pH <7.1 as dependent variables. Independent variables included fetal heart rate category, mode of delivery, resuscitation, and histological chorioamnionitis. Outcomes of infants delivered at 23 and 24 weeks were also compared. RESULTS: In 23-week pregnancies, fetal heart rate category 2 was associated with improved short-term survival compared to category 3 (OR 1.3, 95% CI 0.11-15.7). Cesarean delivery and histological chorioamnionitis were not predictive of survival [(OR 0.5, 95% CI 0.04-7.1, and OR 0.4, 95% CI 0.02-6.85), respectively]. Long-term survival for infants born at 23 and 24 weeks was 8% and 56%, respectively. CONCLUSIONS: The NICHD fetal heart rate category during labor may be associated with survival for infants born at 23 and 24 weeks of gestation. Cesarean delivery was not associated with improved survival.