Prenatal benzodiazepine use poses risk of adverse pregnancy outcomes

The use of benzodiazepine during pregnancy has been associated with elevated risks of preterm birth and small for gestational age in a recent study.

Researchers used data from the National Health Insurance Research Database of Taiwan and emulated a sequence of open-label, randomized trials during gestational weeks 0–36. Eligibility criteria included pregnancy in gestational weeks 0 to 36, maternal age between 15 and 55 years, and no benzodiazepine use during the preceding 6 months.

A total of 59,521 pregnancies exposed to benzodiazepine (mean age 31.9 years) and 394,956 pregnancies with no such exposure (mean age 31.6 years) were included in the analysis. Outcomes were abortion (spontaneous abortion and elective abortion), stillbirth, preterm birth, and small for gestational age.

Compared with nonexposure, prenatal benzodiazepine use was associated with an increased likelihood of abortion (relative risk [RR], 1.58, 95 percent confidence interval [CI], 1.50–1.66), spontaneous abortion (RR, 1.65, 95 percent CI, 1.55–1.76), and elective abortion (RR, 1.83, 95 percent CI, 1.70–1.98).

In an analysis accounting for competing risks, benzodiazepine use was associated with elevated risks of preterm birth (RR, 1.20, 95 percent CI, 1.18–1.23) and small for gestational age (RR, 1.06, 95 percent CI, 1.00–1.09), with stronger effects observed after exposure during the second trimester.