Is black cohosh safe during pregnancy?

What does the evidence say about black cohosh during pregnancy?

1. Black cohosh may not be safe for use during pregnancy or while breastfeeding, and product quality is a documented concern because some commercial black cohosh products have tested as containing the wrong herb or undisclosed herb mixtures. 1
2. A case report describes a woman who developed severe hyponatremia, with a serum sodium of 114 mmol/L, and altered mental status after taking black cohosh to try to bring on and speed up a prolonged home labor. She needed an emergency cesarean delivery and ICU care before recovering fully. 2
3. Black cohosh's effects appear to work through serotonergic activity rather than an estrogenic one, and researchers note there is no known mechanism with biological plausibility that would explain the liver-injury reports some regulators have flagged. 3
4. It's uncertain whether black cohosh is safe for people with hormone-sensitive conditions such as breast or uterine cancer, and it should not be confused with blue cohosh, an unrelated herb tied to serious complications when used to try to bring on labor. 1
5. No published research on black cohosh's effects on a nursing parent's milk supply, breastmilk levels, or breastfed infants exists, and some clinical references recommend against using it while breastfeeding given that gap along with its possible estrogenic activity. 4

Is black cohosh safe in each trimester?

• First trimester. Black cohosh has no established use in early pregnancy, and NCCIH's consumer guidance says it may not be safe during pregnancy at all. There is no research base showing a benefit that would offset that uncertainty this early on.
• Second trimester. The picture does not change in the second trimester. NCCIH also flags a separate concern: commercial black cohosh products have been found to contain the wrong herb entirely or undisclosed herb mixtures, so even a labeled dose is not a guarantee of what you are actually taking.
• Third trimester. Third trimester is when black cohosh most often comes up, as something people take at home hoping to start labor. A case report describes a person who developed severe hyponatremia and altered mental status after using black cohosh during a prolonged home labor, and needed an emergency cesarean and ICU care. This is not a self-directed option this close to delivery.