Astragalus root in pregnancy: evidence and safety

How does astragalus root work?

The pathway here is proposed rather than demonstrated. LiverTox lists astragalus constituents as triterpene glycosides, saponins known as astragalosides, sterols, fatty acids, isoflavonoids, and polysaccharides, and calls the immunomodulatory, antioxidant, antiviral, and cardiotonic activities attributed to them purported. NCCIH files astragalus as an adaptogen, a category it defines as theorized to stimulate the body's resistance to physical, environmental, and emotional stress, and points to a 2023 review of small studies reporting enhanced immune responses and lower proinflammatory cytokines. None of that work involved pregnant participants, so nothing in it describes how astragalus behaves in a pregnancy.

What does the evidence say about astragalus root in pregnancy?

• NCCIH states that little is known about whether astragalus is safe to use during pregnancy or while breastfeeding, and that animal research suggests potential fetal toxicity during pregnancy. 1
• Oral astragalus at up to 60 grams daily for four months appears safe in general adults, though NCCIH notes comprehensive safety evaluation is lacking. It may interact with immunosuppressant medications, and people with autoimmune conditions are advised to avoid it. 1
• LiverTox reports no published cases of astragalus hepatotoxicity and assigns a likelihood score of E, but notes that large doses cause gastrointestinal upset, diarrhea, nausea, and vomiting from direct irritation of the intestinal lining, and that inhibitory activity against several CYP enzymes raises herb-drug interaction questions. 2
• Pregnant mice given hydroalcoholic extract of Astragalus fascicolifolius manna at 400, 800, and 1,200 mg/kg on gestation days 7 to 14 showed significantly higher pregnancy loss than untreated pregnant controls (p < 0.01), with progesterone falling and FSH and LH rising. The authors concluded the extract has abortifacient properties. 3
• Astragaloside IV, a single purified constituent, lowered fasting glucose and malformation rates in a rat model of gestational diabetes at 10 mg/kg daily. That is an isolated compound in an animal disease model, not evidence that whole astragalus root is safe in human pregnancy. 4

What's on the label?

LiverTox describes astragalus extracts sold as tablets or capsules taken once to three times daily, and also as liquids and teas. Neither source names a standardization marker or a milligram dose for any formulation. NCCIH's figure of up to 60 grams a day for as long as four months describes general adults, not pregnancy. NCCIH also notes astragalus is often combined with other herbs, which is why the front of an immune blend rarely tells you how much of it you are getting.

What should I know before taking astragalus root?

Please consult your healthcare provider before starting, stopping, or stacking supplements in pregnancy, especially if you take prescription medication, live with a chronic condition, or have a procedure or delivery scheduled. Herbal supplements are not required to demonstrate purity; brands that publish third-party test results give the most confidence in what is actually in the capsule.