Your Birth Control Will Be Less Effective If You…

A woman holding a pack of birth control pillsDo birth control and antibiotics mix? There’s evidence that taking antibiotics can interfere with the effectiveness of birth control pills and other hormonal methods.

Birth control pills prevent pregnancy very well. Used correctly, they’re more than 99% effective. But, certain things can interfere with effectiveness. For example, many women forget to take their pills regularly. Certain medicines, including over-the-counter drugs and herbals, may also cause the pill to work less well.

Some doctors always warn women who are taking both hormonal birth control and antibiotics to use a back-up method. But, other doctors don’t mention it. What’s the truth? If you’re on the pill and you need to take penicillin for a sore throat, do you need to worry about getting pregnant?

What the Research Shows

For most women, most birth control pills, and most antibiotics, there shouldn’t be a problem. The pill should continue to work well during the week or two you’re taking the medicine. However, medical studies have found that in some women, common antibiotics can reduce the amount of estradiol, or the hormone in birth control pills, in the bloodstream. If the level of estradiol gets too low, the drug won’t work to prevent pregnancy.