Biophysical and biochemical markers at 35-37 weeks' gestation in the prediction of adverse perinatal outcome

Objective: To investigate the potential value of biophysical and biochemical markers at 35-37 weeks’ gestation in the prediction of adverse perinatal outcome.<br /><br />Methods: Screening study in 3,953 singleton pregnancies at 35-37 weeks. Estimated fetal weight (EFW), uterine artery pulsatility index (PI), umbilical artery PI, fetal middle cerebral artery (MCA) PI, mean arterial pressure (MAP), serum placental growth factor (PLGF) and soluble fms-like tyrosine kinase-1 (sFlt-1) were measured. The detection rate (DR) and false positive rate (FPR) of screening by each biomarker were estimated for preeclampsia, delivery of small for gestational age (SGA) neonate, cesarean section for fetal distress<br />before or during labor, umbilical arterial cord blood pH <7.0 or umbilical venous blood pH <7.1, Apgar score <7 at 5 minutes and admission to the neonatal unit (NNU).<br /><br />Results: Multivariable regression analysis demonstrated that significant prediction of PE was provided by PLGF, sFlt-1 and MAP with DR of 73% at 10% FPR. Prediction of SGA was provided by EFW, PLGF and uterine artery PI with DR of 63% at 10% FPR. Prediction of cesarean section for fetal distress before labor was provided by EFW and umbilical artery PI with DR of 100% at 10% FPR. Prediction of fetal distress in labor was provided by EFW and sFlt-1 with DR of 15% at 10% FPR. There were no significant differences from the normal outcome group in any of the biomarkers for low cord blood pH, low Apgar score or NNU admission.<br /><br />Conclusion: At 35-37 weeks’ gestation, biomarkers of impaired placentation and fetal hypoxemia provide good prediction of PE, SGA and fetal distress before labor, but poor or no prediction of adverse events in labor or after birth.