Trends in antihypertensive prescription for pregnant women with hypertension and their peripartum outcomes before and after label and guideline revisions in Japan

We investigated the trends in the proportion of antihypertensive prescriptions listed in the guidelines for pregnant patients and their pregnancy outcomes before and after regulatory actions in Japan. This retrospective cohort study used the Japan Medical Data Center claims data from January 2005 to April 2020. We identified women who had delivered and had hypertensive disorders before childbirth. To evaluate the influence of regulatory actions (label revision in 2011 and guideline updates in 2014), we divided the study period into three terms based on the year of the last menstrual period. We assessed the time trend of the prescription proportion of antihypertensives and conducted multivariable logistic regression analyses to assess the impact of the investigation terms on pregnancy outcomes (preterm birth, cesarean section, emergency cesarean section, and Hemolysis, Elevated Liver enzymes, and Low Platelets syndrome). Among the 13,797 eligible patients, 1739 (12.6%) were treated with oral antihypertensives during pregnancy. Before the policy revisions, the most frequently prescribed antihypertensive medication was methyldopa, but after the label and guideline revisions, nifedipine was the most frequently prescribed. The trend in the prescription proportion of nifedipine increased ( P < 0.001) and that of hydralazine decreased ( P < 0.001), while those of methyldopa and labetalol showed no significant trend. The adjusted odds ratios for all four pregnancy outcomes showed no significant differences according to the investigation terms. By investigating the three terms before and after the label and guideline revisions, significant changes were identified in the trend of the prescription proportion for pregnant women—an increase in nifedipine and a decrease in hydralazine—but not in pregnancy outcomes.