Middle cerebral artery to umbilical artery resistance index ratio in the prediction of neonatal outcome.

OBJECTIVE

The objectives of this study were to evaluate the usefulness of the middle cerebral artery to umbilical artery resistance index ratio (C/U ratio) as a predictor of adverse perinatal outcome, and to show that the absence of fetal umbilical artery end-diastolic velocity (AEDV) in SGA fetuses is associated with high morbidity and mortality.

METHOD

In this prospective study, color Doppler flow imaging was used for the estimation of the C/U ratio in fetuses that were small for their gestational age, in 70 singleton pregnancies between 29 and 42 weeks of gestation. The subjects were categorized into two groups, with Group A consisting of 35 small for gestational age (SGA) fetuses with a normal C/U ratio (1.05 or higher), and Group B comprising 35 SGA fetuses with an abnormal C/U ratio (below 1.05).

RESULT

The mean C/U ratio values for birth weight and gestational age were higher in group A than in group B. Fetuses born to mothers in group B stayed longer in the neonatal special care unit (NSCU), whereas the period from ultrasound examination to delivery was higher in the cases in group A. A higher percentage of mothers with an abnormal C/U ratio underwent cesarean section. Fetuses with an absent end-diastolic velocity of the umbilical artery had a higher morbidity. Three stillbirths occurred in fetuses with an absent end-diastolic velocity of the umbilical artery.

CONCLUSION

Our results suggest that the C/U ratio is a good predictor of neonatal outcome, and could be used to identify fetuses at risk of morbidity and mortality. Fetal umbilical artery AEDV with intrauterine growth restriction is associated with high perinatal morbidity and mortality.