Magnitude, Preventability, and Determinants of Adverse Drug Reactions Among Hospitalized Obstetric Patients in Ethiopia: A Prospective Observational Study.

Adverse drug reactions (ADRs) are an important and potentially preventable cause of morbidity among hospitalized obstetric patients, with implications for both maternal and fetal safety, yet evidence from low-resource settings remains limited. This prospective observational study, conducted from February to May 2025 at Debre Tabor Comprehensive Specialized Hospital, Ethiopia, aimed to determine the magnitude, characteristics, preventability, and determinants of ADRs among hospitalized pregnant women and postpartum women within six weeks of delivery. ADRs were identified through daily chart review and patient interviews and confirmed using the Naranjo Adverse Drug Reaction Probability Scale, while severity and preventability were assessed using the modified Hartwig and Siegel scale and the Schumock and Thornton criteria, respectively. Multivariate logistic regression was used to identify factors independently associated with ADR occurrence. Among the 354 patients included, 52 experienced at least one ADR, yielding a prevalence of 14.7%. Most ADRs were mild to severe (88.5%) and classified as definitely preventable (82.7%). Polypharmacy (4-6 medications) was independently associated with ADR occurrence (adjusted odds ratio [AOR] = 4.02; 95% CI: 1.63-9.93). Additionally, patients with a history of adverse pregnancy outcomes (AOR = 6.28; 95% CI: 2.64-14.95) and those with underlying medical comorbidities (AOR = 2.95; 95% CI: 2.23-9.76) had significantly higher odds of experiencing ADRs. ADRs were relatively common among hospitalized obstetric patients, and the predominance of preventable events highlights the need for strengthened pharmacovigilance systems and targeted medication safety interventions to reduce preventable harm and improve maternal and fetal outcomes in resource-limited settings.