Analysis of reports of unintended pregnancies associated with the combined use of non-enzyme-inducing antibiotics and hormonal contraceptives

Review of Yellow Card reports provides signal that antibiotics (ABs) may reduce efficacy of hormonal contraceptives. It found that compared with control medicines, unintended pregnancies were 7 times and 13 times more commonly reported with ABs and enzyme inducers, respectively.

BMJ Evidence-Based Medicine