St John's Wort contraception warning reiterated

The herbal remedy St John's Wort could dilute the effectiveness of female contraception methods, such as the pill and implant. Warnings concerning the dangers of mixing the herb with some varieties of contraceptives have been renewed by drug safety chiefs in the wake of some women accidentally falling pregnant despite being on contraception.

According to the Medicines and Healthcare products Regulation Agency, two women fell pregnant toward the end of 2013 despite the fact they both had the contraceptive implant. As a result, the agency was given yellow card reports, which highlighted the suspected interference of medicines or herbal remedies. 

Since the year 2000, some 19 reports have been filed showing the impact that St John's Wort can have in terms of hormonal contraceptives. Of these instances, 15 involved the contraceptive pill while four involved the implant. Some 15 women fell pregnant unexpectedly as a result of the herb's interference, while the other four women experienced irregular menstrual bleeds.

Currently, it is thought that St John's Wort only affects implants like Implanon, as well as the progesterone-only and combined contraceptive pill. It is not yet known whether the herb has any effect upon the coil.

St John's Wort is a herbal remedy that is often taken as a natural treatment for anxiety and mild depression. Packaging for the pill already features information that states the herb should not be taken alongside the contraceptive as it can affect its effectiveness. Patients should also be told of the associated risks by doctors.

The herbal remedy has also been found to impact the effectiveness of immunosuppressants, which could ultimately lead to the rejection of transplanted organs. 

Patients are advised to disclose to doctors if they are taking any herbal remedies as they could lead to larger problems when mixed with medication. This is still the case if the remedies' packaging does not contain any warnings, as unlicensed products or those available on the internet do not always have sufficient information.