Open Source Apothecary At Home / Safety

Pregnancy and breastfeeding: the honest position

Almost no plant has safety data in pregnancy. That is the finding, not a gap in the search.

safety

The safety of a herb in pregnancy is unknown in almost every case, because pregnant people are excluded from trials as a matter of course. "Traditional use in pregnancy" is a claim about history, not about safety, and several plants traditionally used in pregnancy are now recognised as abortifacient, teratogenic, or both.

Plants to avoid in pregnancy by default, because each has a documented mechanism: pennyroyal (pulegone, hepatotoxic and abortifacient), rue, tansy, wormwood, Aristolochia, aloe latex and other stimulant laxatives, comfrey and other pyrrolizidine-containing plants, goldenseal and barberry (berberine), licorice in quantity, and the essential oils that are not used in pregnancy — among them pennyroyal, tansy, sage, rosemary in quantity, and juniper.

The ordinary remedies that are reasonable for ordinary complaints. Ginger has trial evidence for nausea of pregnancy and is the usual first choice. Soluble fibre and adequate fluid for constipation. Nettle or ginger tea for a cold. Warm salt-water gargles for a sore throat. This is a short list because the safe list genuinely is short.

Breastfeeding is a different question with the same shortage of data. Fenugreek and milk thistle are the two most used galactagogues and both have trial literature of low quality; where a review found an effect it was small and confidence was low. Anything that suppresses prolactin or is a dopamine agonist — and that includes large doses of some common herbs — reduces supply, and none of it should be used to self-manage a real or perceived low supply without a lactation consultant or clinician, because the commonest cause is latch and positioning, which no tea fixes.

What the studies found

Cautions and interactions

• Assume unknown unless proven otherwise. A lack of reported harm is not evidence of safety in pregnancy.
• Avoid pennyroyal, rue, tansy, wormwood, Aristolochia, aloe latex, comfrey, goldenseal, and berberine in pregnancy.
• Do not use a herb to start, stop, or sustain labour. That is an obstetric decision with foetal monitoring attached.
• Fenugreek and milk thistle for milk supply: low-quality evidence, and not the first thing to fix. Get latch and feeding position assessed first.

When this is not a self-care problem — get help

• Any bleeding, cramping, reduced fetal movement, severe headache, visual change, or swelling of the face and hands in pregnancy — urgent obstetric assessment, immediately.
• A breast that is red, hot, painful with fever and flu-like aching — this is mastitis and needs prompt medical care, not a poultice alone.

Related

• Nausea and vomiting, including morning sickness
• Breastfeeding and milk supply
• Herb-drug interactions: the ones with numbers behind them

Sources

1. Oral galactagogues (natural therapies or drugs) for increasing breast milk production in mothers of non-hospitalised term infants. The Cochrane database of systematic reviews 2020; doi:10.1002/14651858.CD011505 PubMed 32421208
2. Chinese herbal medicine for endometriosis. The Cochrane database of systematic reviews 2012; doi:10.1002/14651858 PubMed 22592712
3. Chinese herbal medicine for endometriosis. The Cochrane database of systematic reviews 2009; doi:10.1002/14651858.CD006568.pub2 PubMed 19588398
4. Herbal galactagogues to improve breastmilk production and lactation in mothers of preterm babies: a systematic review of clinical trials. European journal of clinical nutrition 2026; doi:10.1136/ebmed-2017-110883 PubMed 41350450
5. Biophysical effects, safety and efficacy of raspberry leaf use in pregnancy: a systematic integrative review. BMC complementary medicine and therapies 2021; doi:10.1186/s12906-017-2052-1 PubMed 33563275