- BACKGROUND: The use of herbal medicines by pregnant women is on the rise. However, there is limited information regarding the safety of these compounds during pregnancy. Therefore, the goal of this study was to explore the consequences of raspberry leaf use during gestation in Wistar rats. METHODS: Female rats were randomly assigned to receive vehicle, raspberry leaf, or specific flavonoids in raspberry leaf (kaempferol or quercetin; 10 mg/kg per day) orally once breeding had been confirmed until parturition. We assessed pregnancy outcomes in the P generation and reproductive development/fertility in the F1 raspberry leaf-exposed female offspring. RESULTS: Raspberry leaf use during pregnancy was associated with increased gestation length and accelerated reproductive development in the F1 offspring. CONCLUSIONS: Results from this study have shown for the first time that raspberry leaf use during pregnancy can have long-term consequences for the health of the offspring and raise concerns about the safety of this herbal preparation for use during pregnancy.