Comparison between three-dimensional placental volume at 12 weeks and uterine artery impedance/notching at 22 weeks in screening for pregnancy-induced hypertension, pre-eclampsia and fetal growth restriction in a low-risk population

Abstract

Objectives: To compare the value of three-dimensional placental volume at 12 weeks and uterine artery Doppler at 22 weeks for predicting pregnancy-induced hypertension (PIH), pre-eclampsia and fetal growth restriction in a low-risk population.

Methods: Over a 20-month period we calculated the placental quotient (PQ = placental volume/crown-rump length) at 11-13 weeks' gestation in all women with singleton pregnancies who booked for delivery in our hospital. At 22 weeks, in the same population, we calculated the mean pulsatility index (PI) of both uterine arteries and the presence of an early diastolic notch was noted. Logistic regression models, the PQ and Doppler parameters were used to compare the two screening methods for subgroups of pregnancy outcome.

Results: Complete outcome data were obtained in 2489 consecutive singleton pregnancies. Logistic regression models for the detection of pre-eclampsia had a sensitivity of 38.5% (PQ) vs. 44.8% (Doppler); for the detection of small-for-gestational age (SGA) the sensitivity was 27.1% (PQ) vs. 28.1% (Doppler) at a specificity of 90%. Taking a PQ of <or= 10th centile, a mean uterine PI of >or= 90th centile and a bilateral notch, the sensitivity for detection of SGA was 25.0%, 20.2% and 22.0%, respectively; for PIH it was 9.5%, 4.8% and 4.8%; for pre-eclampsia without SGA it was 20.0%, 28%, 12%; for PIH/pre-eclampsia with SGA it was 30.8%, 46.1% and 69.2%. In the group with the most severe complications, in which delivery took place before 34 weeks, the sensitivity was 50.0%, 50.0% and 38.9%, respectively.

Conclusions: PQ at 12 weeks and uterine artery Doppler at 22 weeks have similar sensitivities for predicting pre-eclampsia and fetal growth restriction, although uterine artery Doppler is marginally more sensitive for the prediction of pre-eclampsia. While both methods are insufficient for screening in a low-risk population, the PQ method has the potential advantage of being performed in the first trimester.