Assessment of uterine arterial notching as a screening test for adverse pregnancy outcome

OBJECTIVE: The objective of the study was to evaluate the screening potential of routine uterine arterial Doppler ultrasonography as a predictor of adverse pregnancy outcome.

STUDY DESIGN: All women (n = 6579) with singleton pregnancies undergoing a fetal anomaly scan at 18 to 20 weeks' gestation between January 1, 1994, and December 31, 1995, at Ninewells Hospital and Medical School were screened for the presence of uterine arterial notching. Women who had evidence of bilateral notching were rescanned at 22 to 24 weeks' gestation. Outcome measures included proteinuric hypertension, premature separation of the placenta, and birth weight z score.

RESULTS: The sensitivity and positive predictive value of uterine arterial notching as a predictor of adverse pregnancy outcomes was low. For all types of notching and disease, outcome sensitivity was never higher than 44% and positive predictive value was never higher than 27%. In contrast, the relative risk of adverse pregnancy outcome in the presence of uterine arterial notching was uniformly high for all disease outcomes (range of relative risk 3.5-30.7). Significant obstetric morbidity was seen in 57% of women with bilateral notches at 18 to 20 weeks' gestation and 72% of women with persistent bilateral notches.

CONCLUSIONS: As a screening test for adverse pregnancy outcomes, detection of uterine arterial notching is poor. Nevertheless, the presence of bilateral uterine arterial notching is associated with a significantly increased risk of adverse pregnancy outcome. In units performing routine anomaly screening, the addition of maternal uterine arterial Doppler ultrasonography may help to discriminate this small group of women at high risk.