Methodology for Estimating the Risk of Adverse Drug Reactions in Pregnant Women: Analysis of the Japanese Adverse Drug Event Report Database

Safety information regarding drug use during pregnancy is insufficient. The present study aimed to establish an optimal signal detection method to identify adverse drug reactions in pregnant women and to evaluate information in the Japanese Adverse Drug Event Report (JADER) database between April 2004 and November 2014. We identified reports on pregnant women using the Standardised MedDRA Queries. We calculated the proportional reporting ratio (PRR) and reporting odds ratio (ROR) of the risk factors for the two known risks of antithyroid drugs and methimazole (MMI) embryopathy, and ritodrine and fetal/infant cardiovascular events. The PRR and ROR values differed between all reports in the JADER database and those on pregnant women, affecting whether signal detection criteria were met. Therefore we considered that reports on pregnant women should be used when risks associated with pregnancy were determined using signal detection. Analyses of MMI embryopathy revealed MMI signals [PRR, 159.7; ROR, 669.9; 95% confidence interval (CI), 282.4-1588.7] but no propylthiouracil signals (PRR, 1.98; ROR, 2.0; 95% CI, 0.3-15.4). These findings were consistent with those of reported risks. Analyses of fetal/infant cardiovascular events revealed ritodrine signals (PRR, 2.1; ROR, 2.1; 95%CI, 1.4-3.3). These findings were also consistent with reported risks. Mining the JADER database was helpful for analyzing adverse drug reactions in pregnant women.