Second-trimester uterine artery Doppler in the prediction of stillbirths.

OBJECTIVE To examine the role of second-trimester uterine artery Doppler in the prediction of stillbirths. METHODS Uterine artery pulsatility index (PI) was measured at 20-24 weeks' gestation in 65,819 singleton pregnancies. The PI was converted to multiples of median (MoM) and compared in live births and stillbirths. Regression analysis was used to determine the significance of association between log(10) uterine artery PI MoM and gestational age (GA) at delivery in cases of stillbirths. RESULTS There were 306 (0.46%) stillbirths and in 159 (52.0%) of these there was pre-eclampsia (PE), placental abruption and/or birthweight below the 10th percentile (small for gestational age, SGA). In the stillbirths, the uterine artery PI MoM was significantly higher than in live births and was inversely associated with GA at delivery. The uterine artery PI MoM was above the 90th percentile in 80.6% of stillbirths with PE, abruption and/or SGA delivering at <32 weeks' gestation, in 41.9% at 33-36 weeks and in 34.3% at ≥37 weeks, and the respective percentages for stillbirths without PE, abruption or SGA were 15.8, 25.0 and 12.4%. CONCLUSION Second-trimester uterine artery PI is effective in identifying early stillbirths in association with PE, abruption or SGA but not late deaths in the absence of PE, abruption or SGA.