Hypertensive disorders of pregnancy (HDP) are major causes of maternal mortality in Korea, and their incidence may increase with advanced maternal age. We analyzed prescription patterns of antihypertensive drugs for HDP between 2018 and 2022, using claims data from the Health Insurance Review & Assessment Service (HIRA). HDP was defined as cases with both an antihypertensive prescription and a diagnosis of hypertension during pregnancy. Gestational hypertension was defined as hypertension with prescription between 20 weeks before delivery and delivery, with no prior record from 6 months before pregnancy to 20 weeks before delivery. Chronic hypertension postpartum was defined as gestational hypertension that continued to receive medication after 3 months postpartum. A total of 32,121 HDP cases were identified, including 23,598 (73.5%) gestational hypertension and 8,523 (26.5%) chronic hypertension. Nifedipine was the most frequently prescribed drug, used in 86.5% of gestational and 73.8% of chronic hypertension cases, consistent with guidelines. In chronic hypertension, the most common pattern was continued nifedipine use before and during pregnancy, followed by switching from other calcium channel blockers. In gestational hypertension, most women did not progress to chronic hypertension postpartum, and continued therapy after delivery was rare.