Objective: To evaluate the performance of placental bed vascularization in a low-risk population to predict severe pregnancy risks. Vascularization was measured in the first trimester, using 3D power-Doppler vascularization index.
Methods: All women who registered during a period of 3 years for delivery in our hospital were prospectively screened in the first trimester. Power Doppler vascularization index of the placental bed (PBVI) was measured in 4325 women and correlated to 7 outcome groups: 1) normal, 2) IUGR ≤ 3rd centile, 3) delivery ≤ 34 weeks, 4) pregnancy induced hypertension (PIH), 5) all pre-eclampsia (PE), 6) severe PE, 7) severe pregnancy problems (SPP i.e. PIH or PE plus IUGR ≤ 3rd centile and/or delivery ≤ 34 weeks). In addition, measurements of mean uterine artery Doppler at 12 and 22 weeks, placental volume and PAPP-A were also performed on all women and their predictive strength for pregnancy risks was compared with the PBVI.
Results: Severe PE and SPP occurred in 0.6 vs. 1.5% of all pregnancies. First trimester PBVI below the 10th centile detected 60% of severe PE and 66.2% of SPP, the odds ratio being 4.48 (95th CI 1.98-11.82) for severe PE and 9.92 (95th CI 5.55-17.71) for SPP. Second trimester uterine artery Doppler detected 72% of PE and 50.8% of SPP, the odds ratio being 14.58 (95th CI 5.78-36.79) and 5.46 (95th CI 3.18-9.36) respectively. All other measured parameters performed much worse compared to PBVI and 22 weeks uterine artery Doppler.
Conclusion: Placental bed vascularization index could be used for a quick and reliable first trimester assessment of severe pregnancy risks.
Keywords: 3D-power Doppler ultrasound; Fetal growth restriction; First trimester ultrasound; Placental bed vascularization; Pre-eclampsia.
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