Testing the Clinical Significance of Third Trimester Uterine Artery Dopplers in Pregnancies With Fetal Growth Restriction.

Objectives: To analyze the third trimester uterine artery Dopplers with other tools of fetal surveillance in prediction of in utero cardiac function measures and adverse neonatal outcomes in fetal growth-restricted pregnancies.

Methods: Pregnancies with severe or non-severe fetal growth restriction (FGR) (per SMFM guidelines) have been analyzed from an ongoing observational FGR study at a University of Colorado high-risk perinatal center. Fetal biometric values, Doppler indices, and cardiac variables were analyzed in both groups. Different Doppler combinations were tested to identify the best predictors for adverse fetal cardiac and neonatal outcomes.

Results: In a cohort of 102 FGR pregnancies, the incidence of abnormal uterine artery Dopplers was 27.5% in the non-severe FGR group and 25.8% in the severe FGR group. Abnormal uterine artery pulsatility index (PI) had a strong association with abnormal umbilical artery PI, with an odds ratio (OR) of 4.51 (1.32-16.2) (P = .01), and the cerebroplacental ratio had an inverse association with elevated uterine artery PI (OR 0.11, 0.01-0.69, P = .03). The odds of birthweight being less than 10th percentile with abnormal uterine artery PI was 9.2 (1.93-43.6, P = .005) in the non-severe FGR group. Fetuses in the severe FGR group with abnormal uterine artery PI had a higher incidence of rounder fetal hearts (OR 4.42, 1.09-17.9, P = .03).

Conclusion: Although elevated uterine artery Dopplers are significantly associated with lower birthweight and rounder fetal hearts, the lack of strong correlation with other outcome variables indicates that the role of uterine artery Dopplers in fetal growth restriction needs further investigation in studies with a larger sample size.