Using the National Health Insurance Database, a nationwide claims database in South Korea (2009–2023), we designed a nationwide cohort study to evaluate the risk of maternal cardiovascular and pregnancy outcomes associated with continuing versus discontinuing statin therapy before conception. Women who used statins during 24–12 weeks before their last menstrual period (LMP) between 2010 and 2022 were included, stratified by whether they discontinued statins before LMP. The primary outcome was major adverse cardiovascular and cerebrovascular events (MACCE), comprising myocardial infarction, stroke, coronary revascularization, and cardiovascular death. Secondary outcomes included preterm delivery, preeclampsia/eclampsia, other hypertensive disorders of pregnancy, gestational diabetes mellitus, non-live birth, major congenital malformations (MCM), and low birth weight. Propensity scores were estimated from potential confounders, and overlap weighting was applied to control for confounding. Weighted hazard ratio (HR) for MACCE was estimated using a Cox proportional hazards model; weighted risk ratios (RR) for secondary outcomes were estimated using generalized linear models, all with 95% confidence intervals (CIs). Among 13,374 women with preconception statin use, 7,493 (56.0%) continued statin therapy beyond the LMP and 5,881 (44.0%) discontinued. Continued statin use was not associated with a decreased risk of maternal MACCE (HR 1.01, 95% CI 0.73–1.38). Findings were consistent across subgroups stratified by maternal history of atherosclerotic cardiovascular disease and statin lipophilicity. Among secondary outcomes, statin continuation was associated with an increased risk of non-live birth (RR 1.11, 95% CI 1.03–1.20). No other significant associations were observed between statin continuation and adverse pregnancy outcomes. In this nationwide cohort, continuation of statin therapy during the periconceptional period was associated with an increased risk of fetal death but did not confer significant cardiovascular benefit regardless of preexisting atherosclerotic cardiovascular disease. These findings support individualized assessment of the potential risks and benefits of statin use in pregnant women.