Do antibiotics interfere with the efficacy of oral contraceptives?

Recommendations from others

Williams Obstetrics (2001) states that some antibiotics still have in their labeling that they may reduce the effectiveness of OCs, but that this is likely not true.⁹ They do not have a recommendation on how to handle this. The MMWR Recommendations and Reports (2003) recommend that women of reproductive potential on OCs who are also taking rifampin should add a barrier method of contraception.¹⁰ The World Health Organization (WHO) states that there have been suspicions that broad-spectrum antibiotics may lower OC effectiveness based on case reports, but that pregnancy rates are similar among women on OCs and women on both OCs and antibiotics.¹¹ According to the WHO 2003 Expert Working Group, broad-spectrum antibiotics are in Medical Eligibility Criteria category 1, which allows use in any circumstances.¹¹