The clinical value of maternal and fetal Doppler parameters in low-risk postdates pregnancies - a prospective study.

OBJECTIVE: The objective of this study is to determine the clinical significance of maternal and fetal ultrasound Doppler flow indices in postdates pregnancies.

METHODS: This prospective study comprised 120 low-risk pregnant women beyond 40 weeks of gestation. All participants underwent Doppler assessment including of fetal middle cerebral artery (MCA), umbilical, and uterine arteries. Perinatal outcomes were recorded and evaluated for possible associations with Doppler flow values. Adverse perinatal outcomes were defined as umbilical cord arterial pH <7.1, Apgar score <7 at 5 min, neonatal admission to a neonatal intensive care unit, and emergency cesarean section due to abnormal intrapartum cardiotocogram Results: Adverse perinatal outcome rate was 17.5% (n = 21). Doppler indices of umbilical artery, MCA, uterine artery and the cerebroplacental ratio (CPR) did not differ significantly between pregnant women with and without adverse perinatal outcomes. Neonatal birth weight was found to correlate negatively with umbilical artery Doppler indices, including the peak systolic to end diastolic ratio (p = .04), the resistance index (p = .02), and the pulsatility index (p = .01). Doppler values of the uterine artery, MCA and CPR did not correlate with neonatal birth weight.

CONCLUSIONS: The contribution of maternal and fetal ultrasound Doppler to the prediction of adverse perinatal outcomes in low-risk postdates pregnancies is low. Hence, performing routine Doppler examination as part of postdates pregnancy assessments is unlikely to yield significant clinical benefit.