Do antibiotics affect birth control?
In short, some antibiotics affect hormonal birth control, and some don’t. There are lots of different kinds of antibiotics, and like all prescription drugs, they have to pass rigorous tests and trials. Figuring out how common drugs interact with each other is an important part of ongoing drug safety assessment, so we have good evidence to show which medications work well — or poorly — with each other.
Clinical trials on most common antibiotics have shown that the risk of getting pregnant while taking hormonal contraceptives and antibiotics is no different than the risk of getting pregnant while using the hormonal contraceptive without antibiotics.
A large epidemiological U.S. study involving more than 43,000 women concluded that there is no connection between antibiotic use and a decrease in the effectiveness of hormonal contraceptives. Additionally, a systematic review in 2016 based on 29 studies showed no difference in the occurrence of suppressed ovulation (the main effect of hormonal contraceptives) and breakthrough bleeding while taking non-rifamycin antibiotics and hormonal contraceptives.