Clinical Chorioamnionitis Is Not Predicted by Umbilical Artery Doppler Velocimetry in Patients With Premature Rupture of Membranes

Chorioamnionitis substantially increases fetal and neonatal morbidity. Infants born to women with Chorioamnionitis have a fourfold increase in neonatal morbidity. If this condition could be predicted before the clinical manifestation and thereby treated earlier, an improved perinatal outcome might reasonably be expected. Based on the in vitro model of bacteria-induced vasoconstriction and pulmonary hypertension noted in sheep and lambs after exposure to the spent medium of a bacterial culture, we theorized that infected amniotic fluid may produce vasospasm of umbilical and placental vessels, reduce fetal perfusion, and increase perinatal asphyxia, morbidity, and mortality. Umbilical vessel vasospasm may be detected by measuring the systolic-diastolic ratio (SID) of the umbilical artery. Continuous Doppler flow studies of the umbilical artery S/D were performed prospectively on 51 patients with premature rupture of membranes who were not in labor. The most recent test, done within 1 day of delivery, was compared with pregnancy outcome. Ten subjects developed clinical Chorioamnionitis, of whom none had an abnormal S/D. Six of 41 women without clinical Chorioamnionitis had abnormal S/Ds. These data do not support the use of Doppler measurement of the S/D as a predictor of clinical Chorioamnionitis.