Prevalence of exposure to benzodiazepines among pregnant women in Taiwan: A nationwide longitudinal study.

Although more than one hundred studies have examined the prevalence of the use of benzodiazepines and benzodiazepine-like Z-hypnotics (BZDs) among pregnancy events, further analysis of the effects of dosage or type of BZDs is needed. The aim of this study was to examine the prevalence rate of BZDs use in pregnancy events, stratified by trimester over time, with characteristics of the dosage and type of BZDs. This is a retrospective population study based on linking three national databases. We examined the prevalence rates from 2004 to 2017, and contrasted the results based on >0 defined daily dose (DDD) and ≥0.5 DDD. We identified 2,630,944 pregnancy events with live births; 89,897 (3.4%) of the associated pregnancy events had used some form of BZD during pregnancy. The prevalence of BZDs use, as defined by >0 DDD, decreased from 4.1% in 2004 to 2.9% in 2017, indicating a decrease in sporadic use and an increase in stable use within therapeutic doses. Meanwhile, BZDs use defined by ≥0.5 DDD increased from 0.1% in 2004 to 0.4% in 2017. Zolpidem was the most frequently prescribed BZDs, as defined by >0 DDD or ≥0.5 DDD. This national cohort study demonstrates the importance of average dosage in the definition of BZDs use in pregnancy events, and it found opposite trends in the prevalence of use between different dosages.