Objective: Absent end-diastolic blood flow in the umbilical artery identifies growth-restricted fetuses at high risk of perinatal mortality and severe morbidity. We explored antenatal variables predictive of perinatal mortality or severe neonatal morbidity in such fetuses.
Study design: We accessed a cohort of 39 singleton, non-malformed, growth-restricted fetuses with absent end-diastolic blood flow at less than 34 weeks between January 1995 and December 2004. The ratio of umbilical artery pulsatility index to middle cerebral artery pulsatility index was calculated to assess redistribution of the fetal arterial circulation. Prenatal and neonatal variables were compared between subjects with versus those without perinatal mortality or severe morbidity using unpaired Student t test or Fisher exact test. Statistical analysis included stepwise logistic regression and receiver operating characteristic curve analysis. P < .05 was considered significant.
Results: Stepwise logistic regression analysis demonstrated that the last umbilical artery/middle cerebral artery ratio (P = .02) and estimated fetal weight before delivery (P = .02) were independent predictors of adverse neonatal outcome, with an umbilical artery/middle cerebral artery ratio 1.9 or greater having a sensitivity of 75% and a 13% false-positive rate. Umbilical artery/middle cerebral artery ratio alone accounted for 54% of the variability in outcome.
Conclusions: Among preterm growth-restricted fetuses with absent end-diastolic blood flow in the umbilical artery, the umbilical artery/middle cerebral artery ratio is the best predictor of neonatal mortality or severe morbidity.