Herbs to avoid when trying to conceive

How do the options compare?

Options are compared on ACOG or MotherToBaby endorsement, size and quality of pregnancy-specific studies, dosing predictability, time-to-effect, and side-effect profile: the same axes an obstetric clinician would use.

• A safety review titled Dietary Supplements: A Framework for Evaluating Safety concluded that the weight of scientific evidence suggests saw palmetto ingestion poses a risk to unborn male fetuses, an effect tied to its antiandrogenic activity: saw palmetto blocks the enzyme that converts testosterone to DHT, and related antiandrogenic drugs are placed in the strictest pregnancy warning category because of abnormal male genital development documented in animal studies. 1
• A multinational study that classified herbal medicines by pregnancy safety placed black cohosh in the contraindicated category, grouping it with other emmenagogues and uterine stimulants the researchers concluded could result in negative pregnancy outcomes. 2
• Black cohosh extract is typically studied in humans at 40 to 80 mg a day, delivering about 8 mg of triterpene glycosides, and a 2025 toxicity review counted roughly 100 case reports linking black cohosh products to liver injury ranging from enzyme elevations to acute liver failure. 3
• LactMed found no published research establishing dong quai's safety in human pregnancy and advises avoiding it during breastfeeding because of a bleeding-risk interaction with warfarin and antiplatelet drugs, plus photosensitivity reactions; the root is used in Chinese medicine specifically for menstrual and menopausal symptoms. 4
• Pennyroyal oil contains 85 percent pulegone, which cytochrome P450 enzymes convert into liver-toxic compounds that deplete glutathione, and even a small dose, one tablespoon (15 mL), can cause seizures, coma, and multiorgan failure; it was historically used to try to induce abortion, and case reports describe it as particularly dangerous in pregnant women. 5

Which option makes sense?

A comparison can include options that should be avoided or considered only in specific circumstances. Please consult your healthcare provider about the findings and cautions that apply to you.

Disclosure: Pregnancy Smart is a supplement maker. The options compared above sit outside our own product line; this page describes their pregnancy evidence on its own merits.