Histological placental abnormalities and associated factors among malaria smear-positive women delivering at two tertiary hospitals in Uganda: a comprehensive multicenter cross-sectional study

Abstract

Malaria in pregnancy may disrupt placental structure and function, but evidence describing placental abnormal¬ities among malaria-positive women in Uganda remains limited. This study determined the prevalence and pat¬terns of gross and histological placental abnormalities and examined associated factors among malaria smear-positive women delivering at two Ugandan referral hospitals. A multicenter hospital-based cross-sectional study was conducted among 124 malaria smear-positive women delivering at Jinja and Hoima Regional Referral Hospitals between 1st May and 1st September 2023. Placentas underwent standardized gross examination, tis¬sue sampling and haematoxylin-and-eosin histology. The primary outcome was the presence of any recorded histological placental abnormality. Multivariable logistic regression was used to identify independently asso¬ciated factors. Histological placental abnormalities were identified in 79 of 124 placentas (63.7%; 95% CI 55.0–71.6). Placental weight below 500 g occurred in 93 (75.0%) placentas, while 98 (79.0%) had central umbilical-cord insertion and 84 (67.8%) had a diameter of 15–20 cm. Histological lesions were not mutually exclusive. Infarction was the most frequent lesion (62, 50.0%), followed by inflammation (43, 34.7%), fibrin deposition (39, 31.5%), increased syncytial knotting (38, 30.6%), thrombosis (35, 28.2%) and fibrinoid deposi¬tion (33, 26.6%). Maternal age < 20 years was associated with higher odds of histological abnormalities than age ≥ 20 years (aOR 14.54; 95% CI 3.64–58.05; p < 0.001). BMI ≥ 30 kg/m² was associated with lower odds than BMI < 25 kg/m² (aOR 0.19; 95% CI 0.04–0.83; p = 0.027). Histological placental abnormalities were com¬mon among malaria smear-positive women. Placental weight < 500 g was the predominant gross finding, while infarction was the most frequent histological lesion. Maternal age < 20 years and BMI ≥ 30 kg/m² were inde¬pendently associated with the outcome. Malaria prevention and antenatal assessment should be strengthened, particularly for pregnant adolescents, alongside prospective studies with malaria-negative comparison groups