Objective: To evaluate the alteration of vascularization in preeclamptic placentas measured by three-dimensional (3D) power Doppler ultrasound.
Methods: We performed a prospective study of placental vascularization and placental volume in 27 singleton pregnancies complicated by preeclampsia and 41 normal pregnancies from 27 to 39 weeks of gestation. The placental volume was analyzed using the VOCAL imaging analysis program and 3D power histogram was used to calculate the placental vascular indices including vascularization index (VI), flow index (FI) and vascularization flow index (VFI).
Results: Of the 27 preeclamptic pregnancies, 9 were complicated by intrauterine growth restriction and 15 were severe preeclampsia. Furthermore, nine of the preeclamptic pregnancies had abnormal end diastolic flow in the umbilical artery. No significant correlation was noted between the placental vascular indices and gestational age in normal pregnancies. The placental vascular indices including VI, FI and VFI were significantly lower in preeclamptic placentas compared with controls (VI, p < 0.001; FI, p = 0.022; VFI, p < 0.001). Preeclamptic placental volume was also decreased compared with that of the controls (p = 0.002). After adjustment for confounding factors, significant differences were observed in VI and placental volume. However, no correlation was found between 3D power Doppler vascular indices and umbilical artery flow velocities, and neither intrauterine growth restriction nor the severity of preeclampsia could be predicted by the vascular indices.
Conclusion: VI and placental volume are reduced in preeclamptic placenta. Placental vascular indices using 3D power Doppler ultrasound provide insights of placental vascularization in preeclampsia.