Background Use of medications to treat attention-deficit/hyperactivity disorder (ADHD) is increasingly prevalent among women of reproductive age, but little is understood about their potential cardiometabolic effects in pregnancy. We aimed to examine associations between ADHD medication use and cardiometabolic conditions during pregnancy (gestational hypertension, preeclampsia, and gestational diabetes) and the pharmacological treatment thereof. Methods Linking statewide hospital and dispensing data, we conducted a population-based matched cohort study of women who gave birth between January 2014 and June 2021 in New South Wales, Australia (n=312,697). We compared the incidence of cardiometabolic conditions and cardiometabolic medication use during pregnancy among women who used ADHD medications during pregnancy (n=336) with a 1:10 matched cohort of unexposed women, and with women who used ADHD medications in the 12 months before pregnancy (n=252). We used Poisson regression models to calculate risk ratios (RR) and 95% confidence intervals (CI), adjusting for sociodemographic and pregnancy-related factors. Results Compared with unexposed women, women who used ADHD medications during pregnancy had an increased risk of gestational hypertension (adjusted RR:1.76, 95% CI:1.20-2.57) and gestational diabetes (aRR:1.41, 95% CI:1.09-1.82), with slightly elevated risk estimates for preeclampsia (aRR:1.30, 95% CI:0.82-2.05) and cardiometabolic medication use (aRR:1.40, 95% CI:0.97-2.01). Compared with women who used ADHD medications before pregnancy only, risk estimates attenuated for all outcomes except gestational diabetes (aRR:1.76, 95% CI:1.06-2.93). Conclusions Women using ADHD medications had an elevated incidence of cardiometabolic conditions during pregnancy, but it remains unclear to what extent this is attributable to medications rather than the underlying ADHD.