Serious drug interactions in hospitalized pregnant women: clinical relevance and maternal-foetal outcomes

Objectives To evaluate the impact on clinical parameters and maternal-foetal outcomes of serious drug interactions in high-risk hospitalized pregnant women. Methods A prospective cohort study including 571 pregnant women hospitalized between September 2019 and June 2022, with an average age of 30.6 years, mostly diagnosed with hypertensive syndromes (69.7%) and gestational diabetes (57.1%). Drug interactions were characterized daily through Lexicomp®, with monitoring of clinical parameters linked to their mechanisms of action. We used a multivariable logistic regression model with demographic and treatment variables to identify factors associated with drug interactions. In a second model, we analysed the impact of serious drug interactions on clinical outcomes, including maternal-foetal outcomes such as macrosomia, foetal tachycardia, amniotic fluid abnormalities, and prematurity. Key findings We identified 203 pregnant women with one or more serious drug interactions (35.6%), and the risk factors were gestational age (adjusted odds ratio [AOR]: 0.96; 95% CI: 0.93–0.98), diagnosis of hypertension (AOR: 3.00; 95% CI: 2.49–6.41), number of medications (AOR: 1.09; 95% CI: 1.03–1.15), and length of hospitalization (AOR: 1.18; 95% CI: 1.12–1.26). Dipyrone and acetylsalicylic acid co-administration increased systolic blood pressure (AOR: 2.12; 95% CI: 1.01–4.47), while scopolamine and levomepromazine resulted in greater drowsiness (AOR: 5.38; 95% CI: 1.66–17.40) and a temperature increase (AOR: 5.96; 95% CI: 1.23–28.98). Conclusion High-risk pregnant women of lower gestational age or with hypertensive syndromes are exposed to severe drug interactions, yet these interactions show limited clinical impact and do not significantly affect maternal-foetal outcomes.