First trimester uterine Doppler and three-dimensional ultrasound placental volume calculation in predicting pre-eclampsia.

OBJECTIVE

To compare the efficacy of uterine artery Doppler velocimetry and three-dimensional ultrasound placental volume calculation alone or in combination in predicting at 11-14 weeks of gestation those pregnancies who will develop pre-eclampsia.

STUDY DESIGN

This was a prospective study of 348 nulliparous women scheduled for a routine prenatal ultrasound examination at 11-14 weeks. Color and pulsed wave Doppler was used to obtain uterine artery flow velocity waveforms transabdominally and the mean pulsatility index (PI) of the uterine arteries was calculated. The placental volume was measured by three-dimensional ultrasound using the virtual organ computer-aided analysis. Outcome variables considered were pre-eclampsia and pre-eclampsia requiring delivery <32 weeks.

RESULTS

Pre-eclampsia developed in 4.1% of the patients studied and in 1.7% a delivery before 32 weeks was required. Placental volume resulted significantly lower in pregnancies who will develop pre-eclampsia (t=4.636, p<0.003) and this was particularly evident in those pregnancies delivering <32 weeks (t=9.704, p<0.0002). No relationship was found between placental volume and mean uterine artery PI (r=-0.08, p=0.327). Uterine artery PI and placental volume showed similar sensitivities in predicting pre-eclampsia (50% vs. 56%) and pre-eclampsia with delivery <32 weeks (66.7% vs. 66.7%). The combination of uterine artery PI and placental volume gave better results when compared to the single use of one of these parameters (pre-eclampsia sensitivity 68.7%, pre-eclampsia requiring delivery <32 weeks 83.3%).

CONCLUSIONS

The combination of abnormal uterine artery Doppler and low placental volume at 11-14 weeks achieves better results than does either test alone in the prediction of pre-eclampsia.