Umbilical cord pH and base excess values in relation to neonatal morbidity for infants delivered preterm

OBJECTIVE: Our purpose was to determine the relationship/predictive value of umbilical cord pH and base excess (BE) values to adverse neonatal outcomes for preterm infants. STUDY DESIGN: A tertiary center perinatal/neonatal database was used to obtain umbilical cord pH and BE values, adverse neonatal outcomes, and patient demographics for preterm (PT, 32-36 weeks gestational age) and very preterm (VPT, 25-32 weeks gestational age) singleton live-born infants delivered between November 1995 and March 2002. RESULTS: PT (n=1807) and VPT (n=603) groups demonstrated a significant inverse curvilinear relationship of umbilical cord pH and BE values to Apgar score <7 at 5 minutes, respiratory distress syndrome, assisted ventilation, and intraventricular hemorrhage/periventricular leukomalacia. Receiver operating characteristic area under the curve values ranged from 0.69 to 0.86 (PT) and 0.70 to 0.87 (VPT). There was little difference between umbilical vein, umbilical artery, pH, or BE in predictive value. CONCLUSION: Umbilical cord pH and BE are related to subsequent adverse outcome events for infants delivered preterm. Worsening acidosis is associated with progressively greater increases in these outcomes with no discriminatory value within or between umbilical artery and umbilical vein pH and BE.