Horse Chestnut in pregnancy and breastfeeding

What NCCIH says about safety

The raw seeds, bark, flowers, and leaves of horse chestnut are unsafe when used orally because they contain a toxic component. Standardized horse chestnut seed extracts, from which this component has been removed, are likely safe for short-term use and have been used safely in research studies for up to 12 weeks. Horse chestnut seed extracts are generally well tolerated but may cause side effects such as dizziness, digestive upsets, headache, and itching in some people. Little is known about whether it’s safe to use horse chestnut seed extract during pregnancy or while breastfeeding.

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

Some studies in people have looked at horse chestnut seed extract for CVI, but very little research has been done on its use for other conditions.

What the research has found

A 2012 systematic review of 17 studies suggested that horse chestnut seed extract can improve symptoms of CVI. Results from one of these studies suggested that horse chestnut seed extract may be as effective as wearing compression stockings. The reviewers noted, however, that there is a need for more rigorous, large-scale randomized controlled trials to assess the efficacy of this treatment option for CVI. Small amounts of research have been done on horse chestnut seed extract for male infertility associated with varicocele (a swelling of veins inside the scrotum) and for irritable bowel syndrome, but there’s not enough information to draw definite conclusions about its effects on either condition.

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.