Abstract / Summary
To describe the mean number of medications used as well as the prevalence of medication use throughout pregnancy in Europe and North America, with a focus on use by trimester, type of medication, and use of harmful medications. A systematic review was performed searching MEDLINE, EMBASE, Cochrane Library, ClinicalTrials.gov and the WHO ICTRP from database inception to August 1, 2025 (CRD42023411090). We included population-based observational study describing medication use in pregnancy in Europe and North America. Medication use was defined as prescription, dispensing, or reported intake of medication. Two reviewers independently checked citations for eligibility, collected data, and assessed the risk of bias using the JBI Critical Appraisal Checklist. Because of substantial heterogeneity, no meta-analysis was performed. Data were reported as medians and interquartile range [IQR]. From 17,304 citations, we included 67 studies over a 50-year period (with study periods ranging from 1971 to 2021) involving around 17 million pregnant women and conducted in North America ( n = 16, 23.9%), northern Europe ( n = 18, 26.9%), western Europe ( n = 22, 32.8%), and southern Europe ( n = 11, 16.4%). Women used 3.3 [IQR:2.3–6.4] different medications during pregnancy, 75.3% [IQR:59.6–88.4] using at least one medication. The number of medications used seemed higher in western Europe, than in southern Europe, northern Europe and North America (6.4 [IQR:4.2–10.2] vs 2.2 [IQR:1.3–2.7], 2.8 [IQR:2.1–3.3], and 2.4 [IQR:1.7–3.7] respectively). The prevalence of women using any medication during pregnancy was also highest in western Europe (89.9% [IQR:78.9–95.1]), followed by southern Europe (80.4% [IQR:73.1–83.4]), northern Europe (71.7% [IQR:54.3–86.1]), and North America (62.3% [IQR:56.3–74.5]). There was no evidence of temporal trend. Anti-infectives for systemic use and alimentary tract and metabolism classes of medications were the most commonly used. The prevalence of use of medication considered harmful ranged from 0.9% to 7.8%, with the highest estimates for the first trimester. Medication use was frequent during pregnancy in Europe and North America, especially in western Europe. An undeniable proportion of pregnant women were exposed to medications considered harmful. The high heterogeneity in medication reporting highlights a strong need for standardized reporting of medication exposure during pregnancy and harmonization of risk classifications. CRD42023411090.