NPLEX II Botanical Medicine Practice Test

In the first trimester, the safest rule is to avoid herbs that can alter uterine activity or hormonal balance, because these changes can influence implantation or early fetal development. Viburnum prunifolium (black haw) is considered contraindicated in early pregnancy because it acts on uterine smooth muscle and can modify uterine tone. That potential to influence the uterus during a very sensitive period is why it’s avoided, making it the herb of concern in this question.

The other herbs in the set have different profiles and aren’t singled out in standard first‑trimester safety guidance for this specific context. Vinca species contain potent alkaloids and carry toxicity concerns, and Vitex agnus-castus modulates pituitary hormones, which is why many clinicians avoid it during pregnancy as well. However, the item’s framing designivly marks viburnum prunifolium as the contraindicated option in the first trimester.