Can adverse neonatal outcome be predicted in late preterm or term fetal growth restriction?

OBJECTIVE

To identify independent predictors of adverse neonatal outcome in cases of fetal growth restriction (FGR) at > or = 34 weeks.

METHODS

From a cohort of 481 FGR cases delivered at > or = 34 weeks, demographic and obstetric variables, fetal biometry and Doppler indices of the uterine, umbilical and fetal middle cerebral arteries available within 2 weeks of delivery, were related to adverse neonatal outcome, defined as admission to the neonatal intensive care unit for indications other than low birth weight alone.

RESULTS

Logistic regression analysis showed that gestational age (GA) at delivery (odds ratio (OR) = 0.59; 95% CI, 0.50-0.70), abdominal circumference (AC) centile (OR = 0.69; 95% CI, 0.59-0.81) and umbilical artery (UA) pulsatility index (PI) centile (OR = 1.02; 95% CI, 1.01-1.04) significantly correlated with adverse neonatal outcome. From this model we calculated a score of adverse neonatal outcome expressed by the formula: (UA-PI centile/3) - (10 x AC centile) + (10 x (40 - GA at delivery in weeks)). Receiver-operating characteristics curve analysis demonstrated that a score of > or = 25 optimally predicted adverse neonatal outcome (sensitivity of 75%, false-positive rate of 18%). Beyond 37.5 weeks, gestational age no longer had an independent impact on outcome.

CONCLUSIONS

In late preterm or term FGR, GA at delivery is the most important predictor of adverse neonatal outcome. At > 37.5 weeks, delivery may be the best option to minimize adverse outcome in all FGR cases. At 34-37 weeks, a score based on GA at delivery, UA-PI centile and AC centile optimally predicts adverse neonatal outcome.