A range of complementary therapies are now commonly used to help reduce the incidence of chronic disease and generally improve health and wellbeing. With any form of treatment it is important to identify side effects and/or adverse events and demonstrate that the benefits of treatment outweigh the risks. Women of reproductive age are one of the largest groups of users of natural medicine. A critical review of 14 studies found that the prevalence of complementary medicine use by pregnant women ranged up to 87%. A longitudinal study of 11,454 women found that three out of four women used complementary medicine, with 50% of them using it on more than one occasion. This study reported a range of adverse events involving women diagnosed with polycystic ovarian syndrome using complementary medicine (including, naturopathy, chiropractic, acupuncture, massage, osteopathy, reflexology, homoeopathy and kinesiology). This study reported 37 adverse events to nutritional and herbal supplements, Traditional Chinese Medicine (TCM) and acupuncture. Nine adverse events were to vitamins, seven to fish oil, six to TCM (two to acupuncture), two to herbal teas and five to vitamin supplements. The adverse events reported in this study included longer menstrual cycles, bowel habit changes, sleep disturbance and headaches.