The clinical value of combining maternal serum screening and uterine artery Doppler in prediction of adverse pregnancy outcome.

Uterine artery Doppler waveform analysis is not offered in routine antenatal care in the UK. The aim of this study is to evaluate a policy of offering uterine artery Doppler ultrasound, in the setting of a District General Hospital, to women who are judged to be at high risk of adverse pregnancy outcome, based on their mid-trimester biochemical serum screening. Data from 73 cases with abnormal serum screening were collected and analysed. Abnormal outcome occurred in 11 cases (16%) including two perinatal deaths. The positive predictive value of adverse outcome was 13% for abnormal serum screening, 26% for human chorionic gonadotropin (hCG) >3 multiples of the median (MOM) and 8% for alfa-fetoprotein (AFP) >2.5 MOM. A total of 56 cases of the study group had uterine artery Doppler at 22 weeks' gestation. Evaluation of the performance of uterine artery Doppler in prediction of adverse pregnancy outcome revealed a sensitivity of 43%, specificity of 70%, a positive predictive value (PPV) of 18% and a negative predictive value (NPV) of 89%. When the presence of diastolic notch was taken to define a positive result the sensitivity remained unchanged, however the specificity, PPV and NPV improved to 91%, 43% and 91%, respectively. In conclusion, the combination of serum markers and abnormal uterine artery Doppler ultrasound improves the identification of women at risk of subsequent pregnancy complications. Raised serum hCG has a better predictive value for adverse pregnancy outcome as opposed to raised serum AFP. In the absence of diastolic notch, the accuracy of abnormal uterine artery Doppler ultrasound is markedly reduced.