Does Fetal Pulmonary Venous Flow Impedance Increase in Pregnancies With Placental Insufficiency-Related Oligohydramnios in the Third Trimester?

Abstract

In placental insufficiency, alteration of left heart compliance occurs, with consequent increased placental vascular impedance. Pulmonary vein flow patterns could reflect altered left atrial pressure. Although the fetal pulmonary venous pulsatility index (PVPI) has been reported as an early marker to evaluate fetal cardiac dysfunction, no studies have been focused on its correlation with oligohydramnios. The aim of this study was to determine whether fetal pulmonary venous flow impedance was greater in women with placental insufficiency-related oligohydramnios than in women with adequate amounts of amniotic fluid during the third trimester. The fetal PVPI and the umbilical arterial systolic-to-diastolic (S/D) ratio were measured by Doppler echocardiography in 130 pregnant women between 28 and 39 gestational weeks. Pregnant women were divided into 2 groups according to the amount of amniotic fluid. The PVPI and umbilical arterial S/D ratio were compared between 19 pregnancies with oligohydramnios and 111 with adequate amniotic fluid. The mean gestational age and estimated fetal weight were not significantly different between the groups. The maternal age was higher in the oligohydramnios group than in the control group (mean ± SD, 36.89 ± 5.88 versus 34.06 ± 4.79 years; P = .023). The mean PVPI was significantly higher in the oligohydramnios group than in the control group (1.13 ± 0.22 versus 0.89 ± 0.31; P < .001). There was no significant difference in umbilical arterial S/D ratio between the groups (P = .142). The PVPI could be used as an early diagnostic marker of fetal deterioration in placental insufficiency-related oligohydramnios.