St. John’s wort does not interfere with the contraceptive effect of the “pill”
Nothing has changed: St. John’s wort (Hypericum perforatum) is regarded as the best tolerated antidepressant and may therefore also continue to be prescribed – with statutory health insurance (SHI) reimbursement – for moderate depression. Nevertheless, there has been repeated speculation that the active constituents of this valuable herbal remedy might interfere with hormonal balance in women and adversely affect the contraceptive effect of the “pill” in particular. Two teams of researchers have now investigated this question.
In a randomised, controlled trial conducted in 18 healthy young women between the ages of 18 and 35 years, the suspected interaction between St. John’s wort and oral contraceptives was investigated by Dr. Arabelle Pfrunder’s research team at Basel University Hospital. During concomitant administration of hypericum extract (LI160) and a low-dose contraceptive pill, the women’s blood hormone levels were determined and follicular maturation in their ovaries was monitored by endosonography. In addition, details of any mid-cycle bleeding were recorded.
Conclusion: The hypericum extract tested did not interfere with follicular maturation or lead to significant changes in blood concentrations of oestrogen or progesterone. There were also no instances of ovulation. The only finding during the course of [treatment] was an increased rate of mid-cycle bleeding. For this reason in particular, the authors advise that women using a contraceptive pill comparable to the study medication (containing 0.02 mg ethinyloestradiol and 0.150 mg desogestrel) should exercise caution when taking St. John’s wort. However, the study conclusions cannot be generalised either to a different hypericum extract or to other oral contraceptives.
The second study was performed by Cornelius Schüle’s research team at the Department of Psychiatry, Munich University. The scientists investigated whether and to what extent a hypericum extract (WS 5570) influences male hormonal balance. Hormone concentrations of cortisol, growth hormone, prolactin and ACTH were studied in 12 healthy men after ingestion of the hypericum extract.
Conclusion: A measurable stimulatory effect was recorded only for ACTH secretion. The ingestion of high-dose hypericum extract had no effect on growth hormone levels or on prolactin or cortisol.
Full documentation on both scientific studies can be found on the Internet pages of the Committee for Research into Natural Medicine e.V. (CRNM) at www.crnm.de and http://www.phytotherapie-komitee.de/
CRNM 1/2005 – 10 January 2005