- Objective. The purpose of this study was to determine the value of bilateral uterine artery notching in the second trimester in the risk assessment for preeclampsia, gestational hypertension, and small-for-gestational-age (SGA) without preeclampsia. Methods. This prospective cohort study included 4190 singleton pregnancies that underwent ultrasound examination between 23 and 25 weeks' gestation. The 95th percentiles of the mean pulsatility index (PI) and resistive index (RI) of both uterine arteries were calculated. Multivariable logistic regression analyses were performed to determine if bilateral uterine artery notching is an independent explanatory variable for the occurrence of preeclampsia, early-onset preeclampsia (≤34 weeks), late-onset preeclampsia (>34 weeks), gestational hypertension, and delivery of an SGA neonate without preeclampsia, while controlling for confounding factors. Results. (1) The prevalence of preeclampsia, early-onset preeclampsia, late-onset preeclampsia, SGA, and gestational hypertension were 3.4%, 0.5%, 2.9%, 10%, and 7.9%, respectively; (2) 7.2% of the study population had bilateral uterine artery notching; and (3) bilateral uterine artery notching was an independent explanatory variable for the development of preeclampsia (odds ratio [OR], 2.1; 95% confidence interval [CI], 1.28-3.36), early-onset preeclampsia (OR, 4.47; 95% CI, 1.50-13.35), and gestational hypertension (OR, 1.50; 95% CI, 1.02-2.26), but not for late-onset preeclampsia or SGA. Conclusions. Bilateral uterine notching between 23 and 25 weeks' gestation is an independent risk factor for the development of early-onset preeclampsia and gestational hypertension. Thus, bilateral uterine artery notching should be considered in the assessment of risk for the development of these pregnancy complications.