COVID exposure during pregnancy reveals alterations in placental histopathology: A research study on Kolkata, India populations.

Objective Exploration of the impacts of COVID exposure (not an active infection) on pregnancy and placental histopathology. Design Observational study. Setting The survey and placenta collection was conducted in tertiary-care hospitals in Kolkata, India. Histopathology experiments were done in the laboratory. Population or sample A cohort of 60 pregnant women (30 control and 30 exposed) in Kolkata, India. Methods An exposure scoring system was assigned based on common COVID exposure routes such as contact frequency, clinical risk factors and symptom history. Clinical parameters were recorded and correlated with histopathological findings of haematoxylin-eosin-stained placental sections. Statistical analyses included Mann-Whitney U test, Chi-square test, Odds ratio estimation and Logistic regression. Main outcome measures Higher exposure scores were associated with alterations in placental morphology; however, no independent association with clinical outcomes was observed. Results Higher pregnancy complications were observed in COVID-exposed pregnant women (odds ratio=4.5, p<0.05). Placental abnormalities were markedly elevated in the exposed group with increased fibrin deposition (73.4% vs 13.15%, p<0.01), crowding of villi (9.4% vs 0%, p<0.01) and calcification (8.9% vs 2.1%, p<0.05). Normal histology was dramatically reduced among exposed patients (7.83% vs 67%, p<0.01). Conclusion Even without active infection at delivery, maternal exposure to COVID-19 during pregnancy is associated with adverse histopathological changes in the placenta. The novel exposure scoring model developed here provides an effective framework for quantifying infection risk and its biological implications.