Screening for the compromised fetus: A randomized trial of umbilical artery velocimetry in unselected pregnancies

Abstract

OBJECTIVE: Meta-analysis of randomized trials of Doppler ultrasonography in high-risk pregnancies has shown reduced mortality rates among normally formed fetuses. This trial addressed the impact on outcome of umbilical artery velocimetry in a nonselected population (i.e., as a screening test in low-risk and high-risk pregnancies). STUDY DESIGN: A randomized, controlled trial with Doppler ultrasonographic investigation was performed at two gestational age windows: 26 to 30 weeks and 34 to 36 weeks. The 2986 women were randomly allocated to revealed or concealed groups in which the Doppler results were either made available or not made available to clinicians; 1056 women were studied at only the first window, 544 at only the second, and 1386 at both. RESULTS: There were no significant differences between groups in antenatal admissions to hospital, preterm deliveries, rates of cesarean section, admission to the neonatal unit, and need for assisted ventilation. There was, however, a trend toward fewer stillbirths in the “revealed” group (three vs eight, odds ratio 0.34, confidence interval 0.10 to 1.07). CONCLUSIONS: The incidence of stillbirths was reduced by more than half in the Doppler-revealed group, but the confidence intervals were wide and these findings could be compatible with chance. (AM J OBSTET GYNECOL 1994;170:555-9.)