Umbilical and fetal middle cerebral artery Doppler at 35-37 weeks’ gestation in the prediction of adverse perinatal outcome

摘要

Objective: To investigate the potential value of cerebroplacental ratio (CPR) at 36 weeks’ gestation in the prediction of adverse perinatal outcome. Methods: Screening study in 6,178 singleton pregnancies at 35-37 weeks. Umbilical artery (UA) and middle cerebral artery (MCA) pulsatility index (PI) were measured, the values were converted to multiples of the median (MoM) after adjustment from variables in maternal characteristics and medical history that affect the measurements and the CPR was calculated by dividing MCA PI MoM with UA PI MoM. Multivariable logistic regression analysis was used to determine if CPR had a significant additional contribution to maternal characteristics, medical history and obstetric factors in predicting adverse outcome. The detection rate (DR) and false positive rate (FPR) of screening by CPR were estimated for stillbirth, cesarean section for fetal distress, umbilical artery cord blood pH <7.0, umbilical venous cord blood pH <7.1, Apgar score <7 at 5 minutes and admission to the neonatal unit (NNU) and neonatal intensive unit (NICU). Results: There was a linear association between CPR and both birth weight Z-score and arterial or venous umbilical cord blood pH, but the steepness of the regression lines was inversely related to the interval from assessment to delivery. The performance of low CPR <5th percentile in screening for each adverse outcome was poor with DR of 6-15% and FPR of about 6%. In the small subgroup of the population delivering within two weeks of assessment, the DR improved to 14-50%, but with a simultaneous increase in FPR to about 10%. Conclusion: The performance of CPR in routine screening for adverse perinatal outcome at 36 weeks’ gestation is poor.