Diagnostic Accuracy of Doppler Ultrasound in Predicting Perinatal Outcome in Appropriate for Gestational Age Fetuses: A Prospective Study

Objective To elucidate the role of Doppler ultrasound in predicting perinatal outcome in appropriate for gestational age (AGA) fetuses at term. Material and Methods Prospective study carried out in a dedicated research ultrasound clinic. The inclusion criterion was AGA fetuses, defined as those with an estimated fetal weight between the 10th and 90th percentile, at 36 + 0-37 + 6 weeks of gestation. The primary outcome was a composite score of adverse perinatal outcome including either adverse intrapartum events or abnormal acid-base status at birth. Secondary outcomes were the individual components of the primary outcome. The Doppler parameters explored were umbilical artery (UA) PI, middle cerebral artery (MCA) PI, uterine arteries (UtA) PI and cerebroplacental ratio (CPR). Attending clinicians were blinded to Doppler findings. Logistic regression and ROC curve analyses were used to analyze the data. Results 553 AGA fetuses were included. There was no difference in mean UA PI (p = 0.486), MCA PI (p = 0.621), CPR (p = 0.832) and UtA PI (p = 0.611) between pregnancies complicated by composite perinatal morbidity compared to those not complicated by composite perinatal morbidity. In pregnancies complicated by adverse intrapartum outcome, the mean MCA PI (1.47 ± 0.4 vs 1.61 ± 0.4, p = 0.0039) was lower compared to the control group, while there was no difference in UA PI (p = 0.758), CPR (p = 0.108), and UtA PI (p = 0.177). Finally, there was no difference in any of the Doppler parameters explored between AGA fetuses with abnormal acid-base status at birth compared to those without abnormal acid-base status at birth. In the logistic regression analysis, UA PI, MCA PI, CPR, UtA PI, EFW and AC percentiles were not independently associated with composite adverse outcome, adverse intrapartum outcome or abnormal acid-base status at birth in non-SGA fetuses. The diagnostic performance of all of these Doppler parameters for predicting composite adverse outcome, adverse intrapartum outcome and abnormal acid-base status was poor. Conclusion Cerebroplacental and maternal Doppler is not associated with or predictive of adverse pregnancy outcome in AGA fetuses close to term.