264. Prescription of Antihypertensive Drugs in Pregnancy: A study based on health insurance claims data

Abstract

Introduction Hypertensive disorders of pregnancy occurs in 5–10% of pregnant women, but information about antihypertensive drugs prescribed to patients with hypertensive disorders of pregnancy is limited. Objective To clarify the prescription of antihypertensive drugs to pregnant women based on claims data. Methods Based on health insurance claim (claims) data at the Japan Medical Data Center, data were extracted about pregnant women with a hypertension-related diagnosis (ICD-10 classification: O10-O16) during pregnancy between January 1, 2008 and May 31, 2010. Information about gestational age and start date of medical care in claims for the mothers was extracted, and based on diagnostic information related to labor and delivery/miscarriage and records of treatment, pregnancy duration for each woman was estimated. Information on drug prescriptions during pregnancy was extracted from medical records or records of dispensed prescriptions. Results From among 2173 pregnant women, information about prescription status during the entire pregnancy could be obtained for 567 women, and of these, 160 women (28%) had been prescribed an antihypertensive drug during pregnancy. The most frequently prescribed antihypertensive drug was nifedipine tablets/capsules (41%), followed by methyldopa tablets (27%) and hydralazine HCl powder/tablets (22%). In addition, diuretics were used in 33%, and renin-angiotensin system drugs were used in 3% of cases. Discussion Safety has not been established for many of the antihypertensive drugs prescribed to women with hypertensive disorders of pregnancy based on our study results. This suggests an urgent need to establish a safety evaluation system for these drugs in Japan.