Antibiotics and How They Affect on Birth Control

December 15, 2022

Dr. Jerry Williams of Urgent Care 24/7 discusses hormonal birth control birth control pills specifically, and how antibiotics affect the effectiveness of hormonal birth control, or birth control pills.

There's been a lot of research done on this and it's frankly been indecisive, on whether antibiotics can actually affect the effectiveness of birth control pills. Birth control, if taken perfectly, the birth control pills are 99% effective, which means one out of 100 women will get pregnant on the birth control. On birth control pills per year, they take the pills perfectly, but if not everyone takes the pills perfectly compliance can be a problem.

The actual effectiveness of oral hormonal birth control pills is about 9% based on typical utilization, which means per year 9% of women per year become pregnant on birth control. How is that affected by antibiotics? Well, it's thought that the antibiotics can actually alter the serum, either bioavailability, meaning the amount of drug available, or alter the levels of the drug actually in the bloodstream. That can make the hormonal therapy birth control pill less effective.

What the typical advice has been is that you should use some kind of a barrier method, either condoms, or spermicidal foam during that period while you're on the antibiotic, and up to seven days after you're off the antibiotic. The research has been unclear on whether there's actually a causation relationship between the antibiotics and the birth control pills and failure of the birth control pills to prevent pregnancy.

To be on the safe side, every physician, every nurse practitioner, PA, that Dr. Williams knows, recommends that patients use an alternative barrier method during that period that we just discussed, he would bring up the fact that a lot of patients are resistant to barrier methods, they don't want it. They're just willing to accept the risk, and others are, they don't want to use the barrier method, we have some patients go look, I'm just not gonna be sexually active during this period of time until it's at least a week after I finished my antibiotics. So abstinence is of course, as you well know, the most thorough form of birth control.

So either way, Dr. Williams just wanted you to make an informed decision if you get on antibiotics and your own oral birth control, birth control pills. It's really, really important to remember that there is a potentially increased risk for becoming pregnant during that period of time while you're on the antibiotic and up to seven days after you just continue the antibiotic.

Dr. Williams hopes that's helpful and he looks forward to seeing you again soon on one of our medical chats.

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