St. John’s Wort (hypericum perforatum) and breastfeeding: concentrations of hyperforin in nursing infants and breast milk

Objective: Herbal preparations for depression such as St. John's Wort (SJW) are often preferred over pharmaceutical preparations by mothers and midwives after childbirth because these preparations are available to patients as over-the-counter "natural" treatments and are popularly assumed to be safe.

Method: Five mothers who were taking 300mg SJW, three times daily [LI 160 (Jarsin®, Lichtwer Pharma GmbH, Berlin, Germany)], and their nursed infants were assessed. Thirty-six breast-milk samples (fore- and hind-milk collected during an 18-hour period), and 5 mothers' and 2 infants' plasma samples were analyzed for hyperforin levels by tandem mass spectrometry (LC/MS/MS; LOQ, 0.1ng/ml).

Results: Hyperforin is excreted into breast milk at low levels. However, the compound was at the limit of quantification in the 2 infants' plasma samples (0.1ng/ml). Milk/plasma ratios ranged from 0.04–0.3. The relative infant doses of 0.9%–2.5% indicate that infant exposure to hyperforin through milk is comparable to levels reported in most studies assessing antidepressants or neuroleptics. No side effects were seen in the mothers or infants.

Conclusion: These results add to the evidence that with some precautions the SJW extract LI 160 is safe while breastfeeding.