Placental pathology and maternal risk factors as predictors of adverse neonatal outcomes in small-for-gestational-age births: A prospective cohort study in Northern Uganda

Abstract

Background Births that are small-for-gestational-age (SGA) represent a major cause of neonatal morbidity and mortality, particularly in sub-Saharan Africa. The contribution of specific placental histopathological lesions and their association with maternal risk factors remain poorly characterized in this high-burden setting. This study aimed to determine the incidence of adverse neonatal outcomes in SGA births and to identify associated placental and maternal predictors in northern Uganda. Methods A prospective cohort study was conducted at Lira Regional Referral and Kiryandongo General Hospitals in Uganda from 15 th April 2025 to 15 th August 2025. A total of 151 women delivering singleton SGA infants were enrolled. Maternal sociodemographic, clinical, and obstetric data were collected via a structured questionnaire, and placentas were examined using standardized histopathological protocols. The primary outcome was a composite of adverse neonatal events, including admission to the neonatal intensive care unit (NICU), Apgar score <7 at 5 minutes, preterm birth, or early neonatal death. Multivariable Poisson regression was used to identify independent predictors of the composite outcome. Results The incidence of adverse neonatal outcomes was 48.3% (95% CI: 40.4–56.4). Placental abnormalities were identified in 47.7% of cases, with inflammatory lesions (8.6%), vascular lesions (7.9%), and villous infarctions (6.0%) being the most prevalent findings. After adjusting for confounders, the presence of any placental abnormality was the strongest independent predictor of adverse outcomes (adjusted Relative Risk = 2.23; 95% CI: 1.45–3.43; p < 0.001). Maternal obesity (Body Mass Index ≥30 kg/m 2 ; aRR = 1.61; 95% CI: 1.06–2.46; p = 0.027) and higher maternal income (>200,000 Ugandan Shillings; aRR = 1.66; 95% CI: 1.03–2.69; p = 0.037) were also significantly associated with an increased risk of adverse outcomes. Conclusion Nearly half of SGA neonates in this northern Ugandan cohort experienced an adverse neonatal outcome. Placental abnormalities were common and were associated with adverse outcomes, and maternal obesity was identified as a potentially modifiable risk factor. These findings support the value of structured placental examination after SGA deliveries for etiologic classification and risk stratification and highlight the need for further research to determine whether targeted antenatal interventions addressing maternal nutrition and weight management can reduce adverse neonatal outcomes.