First trimester placental and myometrial blood perfusion measured by 3D power Doppler in normal and unfavourable outcome pregnancies

Abstract 

Introduction

To evaluate whether 3D placental and myometrial power Doppler blood perfusion in the first trimester can be used to detect risk pregnancies.

Methods

3D power Doppler vascularization index (VI) and flow index (FI) of the entire placenta and the neighbouring myometrium were separately measured in the first trimester in all women with singleton pregnancies during a period of three months. In addition we measured placental volume, placental quotient, PAPP-A, as well as uterine artery at 12 and 22 weeks (mean PI and mean notch) and compared those data with the pregnancy outcome.

Results

Data from 383 women could be evaluated. 10 developed pre-eclampsia (PE). Both flow and vascularization were markedly lower in the placentas compared to the adjoining decidua and myometria. There was some correlation between placental vascularization Index (PVI) as well as deciduo-myometrial vascularization index (MVI) and placental volume, PAPP-A and number of pregnancies and a marked correlation between PVI and especially MVI to mean notch at 12 weeks and 22 weeks (PVI: −0.215, −0.274 MVI: −0.316,−0.322). PVI and MVI were significantly reduced in women with pregnancy problems and showed the greatest reduction in PE-pregnancies (p: 0.0018, 0.0004). Of all measured parameters MVI showed the best sensitivity for the detection of PE.

Conclusion

The correlation between PVI and MVI in the first trimester and mean notch in the second shows that they provide valuable information at as early as 12 weeks which normally so far is only available at 22 weeks by uterine artery Doppler flow. As MVI measures the percentage of vessels in the deciduo-myometrial area it could also provide information on trophoblast invasion. This hypothesis is supported in particular by a marked decrease of the MVI in pregnancy problems especially in PE-pregnancies.

Keywords: Placental perfusion, Myometrial perfusion, Uterine artery Doppler first and second trimester, Assessment of trophoblast invasion