Women are the highest users of dietary supplements in the United States (US) with recent national data reporting 44.8% of supplement users are non-pregnant and non-lactating reproductive-aged women. (1,2) Supplement use increases each year (3) with botanical or herbal supplements comprising 5.1-8.3% of all dietary supplement use.(1,2) While most available supplement data is focused on adult users, recent data reports 37.3% of female children and adolescents in the US used dietary supplements in the past 30 days.(4)

Adolescents who use dietary supplements are more likely to also use prescription medications. (5) The most common prescription class among adolescents remains contraceptives with increasing use over time. (6) According to the most recent National Survey of Family Growth, 55% of adolescents use a hormonal contraceptive method.(7) Despite herbal supplements frequently being used concomitantly with prescription and over the counter medications (8,9), there remains scant clinical research on herbal-drug interactions. (10, 11, 12) One of the most well-studied interactions is between St. John's Wort and hormonal contraceptive methods.(13) St. John's Wort increases cytochrome P450 (CYP) liver metabolism of steroid hormones via CYP3A4 and CYP2C9 enzyme induction, thus decreasing the effectiveness of hormonal contraception with case reports of both increased unintended pregnancy rates and breakthrough bleeding.(13, 14, 15) Other supplements have demonstrated interactions with hormonal contraception due to phytoestrogenic activity or direct activity on uterine or ovarian receptors.(16,17) These under-studied supplement-drug interactions can lead to potential adverse events such as thrombotic thrombocytopenic purpura with oral contraceptive pills (18), or cardiac arrhythmias and gastrointestinal illness with antidepressants and diabetic medications.(19)

Despite the high prevalence of overlapping supplement and contraceptive use, there remains a paucity of clinically relevant data on supplement usage patterns in women's healthcare and even less in the realm of family planning.(20) To address this knowledge gap, we aimed to evaluate herbal medicine and supplement use patterns including potential adverse effects and interactions among adolescent and young adult women at a family planning focused clinic.