Risk of abnormal fetal growth in women with early- and late-onset preeclampsia

Objectives: To investigate the risks of delivering small-for-gestational-age (SGA) and large-for-gestational-age (LGA) infants in women with early-(delivered before 34 weeks of gestation) and late-onset (delivered at or after 34 weeks of gestation) preeclampsia. Study design: We conducted a retrospective cohort study of 29,494 singleton deliveries after 24 weeks' gestation, excluding pregnancies complicated by fetal anomalies, stillbirths, and prepregnancy diabetes mellitus. Univariate and multivariate logistic analyses adjusted for potential confounding factors, including prepregnancy body mass index (BMI), gestational weight gain (GWG), and gestational diabetes mellitus (GDM), were performed. Results: Among women who delivered before 34 weeks, significantly more women with preeclampsia delivered SGA infants than women without preeclampsia (50.6% vs. 7.0%; adjusted odds ratio [OR] 16.3; 95% confidence interval [CI] 8.1-32.9). Among women who delivered at or after 34 weeks, women with preeclampsia had higher rates of delivering SGA (25.5% vs. 7.0%) and LGA (13.7% vs. 9.9%) infants than women without preeclampsia. After adjustment for confounding factors, preeclampsia remained a significant risk factor for delivering SGA infants (adjusted OR 5.7; 95% CI 4.6-7.1), but the association between preeclampsia and the delivery of LGA infants was diminished (adjusted OR 0.8; 95% CI 0.6-1.1). Conclusions: Our results confirm that preeclampsia is associated with SGA and that the association is stronger with early-onset disease. Although women with late-onset preeclampsia had a higher rate of delivering LGA infants, the association between late-onset preeclampsia and LGA is due to confounding factors, such as high prepregnancy BMI, excessive GWG, and GDM, related to maternal metabolic abnormalities.