Individualized risk assessment for adverse pregnancy outcome by uterine artery Doppler at 23 weeks.

OBJECTIVE: To provide individualized risk prediction of severe adverse pregnancy outcome based on uterine artery Doppler screening at 23 weeks. METHODS: Color Doppler assessment of the uterine arteries was carried out in 5121 women attending for routine care at 23 weeks in two inner-city obstetric units. The mean uterine artery pulsatility index (PI) was calculated, and the likelihood ratios in relation to PI were generated for severe adverse outcome. This was defined as fetal death, placental abruption, and delivery before 34 weeks associated with preeclampsia and birth weight less than the 10th centile. RESULTS: The likelihood of severe adverse pregnancy outcome increased quadratically with mean uterine artery PI. This relationship was not affected by maternal age, ethnicity, or parity. At a mean PI of 1.45, the 95th centile for our population, the likelihood ratio for severe adverse pregnancy outcome was 5. Cigarette smoking had an additional contribution to PI in predicting severe adverse outcome, roughly doubling the risk for a given PI. CONCLUSION: The individualized risk of severe adverse pregnancy outcome can be determined by uterine artery Doppler screening at 23 weeks and knowledge of cigarette smoking history. Such individualized risk would allow ultrasound resources and clinical follow-up to be tailored to the pregnant woman for the most appropriate use of antenatal care.