Hypericum perforatum use during pregnancy and pregnancy outcome

•Association between hypericum perforatum(HP) during pregnancy and pregnancy outcome.•Information on more than 90,000 pregnancies was obtained from the Danish National Birth Cohort.•Only 38 women reported use of HP during pregnancy.•HP use was not associated with the pregnancy outcomes investigated.•There were more malformations than expected (based on 3HP exposed cases p> 0.05).

Hypericum perforatum (HP; also known as St. John's Wort) is one of the most commonly used herbal therapies in the management of depressive illness. The aim of this study was to evaluate the potential side effects of HP during pregnancy on pregnancy outcome. Using data from the Danish National Birth Cohort (DNBC), we investigated outcomes among 38 HP exposed pregnancies compared to a group of 90,128 women. Associations between HP use and gestational age, preterm birth, birth weight, malformations and Apgar scores were investigated. Preterm birth did not differ across the groups. While the prevalence of malformations in the HP exposed group was slightly higher (8.1%) than observed in the control groups (3.3%; p = 0.13), this was based on only three cases and was not of any specific pattern.