St. John's Wort in pregnancy and lactation

Filed under: Your Pregnancy, Health & Safety: Babies, Nutrition: Health

St. John's wort (hypericum perforatum) is one of the five best-selling herbs in the United States. It is used by many to treat the symptoms of depression, and many prefer it to prescription medications. However, the herb has been the subject of growing concern about its interaction with birth control pills, the blood thinner warfarin, and cyclosporin, a medication used with those who have received organ transplants. A new study examining its effect on pregnant women and those who are breast-feeding contributes to the evidence that the product should be used with caution.

The study will soon be published in the Canadian Journal of Clinical Pharmacology but was presented at the recent 21st Annual Meeting of the American Association of Naturopathic Physicians ( It was basically a thorough review of the literature and found that varying levels of scientific evidence on the efficacy of use for different conditions; low-level evidence of harm during pregnancy; and strong evidence of side effects during lactation. As St. John's wort interacts with a number of medications due to its effect on cytochrome P450 enzymes, this may account for some of the findings. The researchers concluded:
  • Caution is warranted when using St. John's wort during pregnancy and lactation. St. John's wort may interact with medications prescribed during pregnancy.
  • During pregnancy, a case study and some animal studies reported lower birth weights with use of St. John's wort. Strong scientific evidence showed that St. John's wort consumption during lactation did not affect maternal milk production nor affect infant weight, but may cause colic, drowsiness or lethargy.
  • St. John's wort showed strong scientific evidence of being an effective aid in combating mild to moderate depression and low-level evidence for other conditions.
These findings may be useful to those of you who lean towards naturopathic approaches to health care.

ReaderComments (Page 1 of 1)


Flickr RSS



AdviceMama Says:
Start by teaching him that it is safe to do so.