Astragalus in pregnancy and breastfeeding

What NCCIH says about safety

Astragalus may be safe when used orally. (Taking up to 60 grams per day for as long as 4 months does not seem to cause adverse effects.) However, a thorough safety evaluation has not been done. There isn’t enough reliable information to know if applying astragalus to the skin is safe or has potential side effects. Because astragalus might worsen symptoms of autoimmune diseases, people with autoimmune diseases should avoid using astragalus. Also, astragalus may interact with medications that suppress the immune system. If you take any type of medicine, talk with your health care provider before using astragalus or other herbal products; some herbs and medicines interact in harmful ways. Little is known about whether it’s safe to use astragalus during pregnancy or while breastfeeding. Some research in animals suggests that during pregnancy, astragalus can be toxic to the fetus.

Quoted in full from NCCIH so nothing is lost in summarising. Where they say “little is known”, that means the studies do not exist — not that the herb is known to be safe, and not that it is known to be harmful.

How much is actually known

There is not sufficient reliable scientific evidence to know whether astragalus is useful for any health condition.

What the research has found

Recent scientific reviews have evaluated the research on astragalus for various conditions. A 2024 review of 20 studies (involving 953 adults with type 2 diabetes) found that taking astragalus in addition to the medicine metformin reduced fasting blood glucose and hemoglobin A1C more than metformin alone. (HbA1C measures the average blood glucose over the prior few months.) Most of the studies, however, were of low quality and found to have bias. A 2023 review of 19 studies (involving 1,094 participants) found that astragalus enhanced immune responses and reduced levels of proinflammatory cytokines. (A cytokine is a type of protein made by certain immune and non-immune cells and has an effect on the immune system.) The studies were small, and there were many differences in how the studies were done, however. A 2023 review of 50 studies (involving 3,423 participants) showed that adding astragalus to supportive care or immunosuppressive therapy for treating the kidney disorder membranous nephropathy resulted in greater improvements in some indicators of kidney health. The authors of the review cited several problems with the studies, including their low quality, small size, and limited geographical location.

Before you take this

Dose and form change the answer completely. A culinary amount of a spice, a cup of tea, and a concentrated supplement extract are three different things, and most research is done on the last of them.

Supplements are also not regulated like medicines, so strength and purity vary between products. Bring the actual bottle to your midwife, doctor or pharmacist — that conversation is worth more than any page, including this one.