Top things to know
I’m on hormonal birth control. Can I get pregnant if I take antibiotics?In most cases, no, as long as you continue to use your hormonal contraception as prescribed you are safe from pregnancy even if you are on antibiotics.
There is however, one class of antibiotics that is the exception: rifamycins (1). What do I need to know about Rifamycins?Rifamycins are a class of antibiotics. The most commonly prescribed rifamycin is known by the name rifampin. (Other types of rifamycins include rifapentine, rifabutin, and rifaximin.) Rifampin is not prescribed very commonly in the United States.
Rifampin can sometimes be used in combination with other antibiotics to treat other bacterial infections too (1). (Fun fact about rifampin: one of the side effects is that it may turn your urine, tears, saliva, and sweat a red color (3).) Rifampin, can speed up the liver’s ability to break down molecules and medications, including hormonal birth controls, which are processed continually through the liver (3). For this reason, anyone taking any form of hormonal contraceptive, like the pill, patch, ring, mini-pill, and the implant, who is prescribed rifampin treatment should note that their hormonal contraceptive will not be as effective, and may increase their likelihood of becoming pregnant (3-5). Rifampin does not interact with other forms of birth control, such as the contraceptive shot, the copper IUD, and the hormonal IUD, meaning that you can continue to use these types of contraception while undergoing rifampin treatment (4,5). What if my healthcare provider prescribes rifampin for me?If your healthcare provider does prescribe rifampin to you, be sure to let them know if you are using a hormonal contraceptive. Unless otherwise stated by your healthcare provider, you can still continue to take your pills as usual every day. However, during this time, it’s important to use non-hormonal birth control methods, like external or internal condoms, or abstain from sex as backup protection during rifampin treatment (3). If you use birth control pills, consider following the recommendations for what to do if you miss two or more pills:
If you are using another form of hormonal contraceptive, like the patch or ring, speak to your healthcare provider. Things to keep in mind, when you’re sickEven if you aren’t on rifampin, being ill is hard on the body and mind. If you are sick, it’s easy to lose track of time and responsibilities, and you might forget to take your pill (or other daily medication). Use Clue to set up pill reminders, or task a family member, partner, or friend, to help remind to make sure to take your contraceptive pill daily at the same time. Use the Clue app to set up daily pill reminders. Most antibiotics (medications designed to fight bacterial infections) do not affect your birth control, with the exception of a few. While some women have gotten pregnant while taking antibiotics and hormonal birth control at the same time, these reports are rare. Your chances of getting pregnant while taking most types of antibiotics are no higher than the normal failure rate of birth control, which is 6 to 9%. How Antibiotics Might Affect Birth ControlSome types of antibiotics have the potential to affect birth control because they can alter the body’s hormone levels. Hormonal birth control methods that these antibiotics might impact include:
All four of these birth control methods contain the hormones estrogen and/or progestin which thickens the mucus in the cervix, making it difficult for sperm to fertilize an egg, and thin the lining of the uterus to reduce the chance of getting pregnant. The methods that contain estrogen also prevent you from ovulating, while progestin-only methods stop ovulation but not consistently. Certain antibiotics can lower the levels of estrogen and progestin in your body, potentially to the point of affecting your birth control. Theoretically, antibiotics might also reduce your birth control’s efficacy by interrupting the recirculation of estrogens in the body — a process called enterohepatic circulation. They do this by killing the bacteria in the small intestine that help break the hormone down and redistribute it within the body. For these reasons, many manufacturers have historically placed warnings on antibiotic labels to inform women about this risk. Over the years, scientists have done many studies on various types of antibiotics’ effects on hormonal birth control to determine which ones you should and should not take at the same time. Antibiotics That Can Affect Birth ControlResearchers have only proven that two types of antibiotics can affect the efficacy of your birth control:
Both of these medications belong to a class of antibiotics called rifamycins. Scientists have not been able to prove that any other rifamycins, however, affect birth control. Antibiotics That Do Not Affect Birth ControlMost antibiotics have no proven effects on hormonal birth control and will not increase your chances of getting pregnant if you have sex during treatment. Commonly prescribed antibiotics that are safe to take while on birth control include:
Some antibiotics can have other side effects that should be taken into consideration. Taking doxycycline or minocycline, for instance, can increase your sensitivity to the sun. Other medications that aren’t antibiotics, such as some antifungals, might have interactions with your birth control too, so always tell your health care provider about all the medications you’re taking. What to Do if You Need to Take Antibiotics While on Birth ControlIf your health care provider prescribes you an antibiotic and you’re concerned about it affecting your birth control, simply use a backup form of birth control during and a week after treatment. These include:
You might also talk to your medical team about switching to nonhormonal birth control, such as a copper intrauterine device (IUD). This small device can be placed in your uterus to prevent sperm from reaching and fertilizing an egg. The copper essentially acts as a spermicide. If your health care provider prescribes you a rifamycin, always use a backup method of birth control, such as a condom or diaphragm, when having vaginal sex. Use one of these backup methods for the entire length of your treatment, plus a week after finishing the antibiotic. If you are taking an antibiotic to treat a sexually transmitted infection such as gonorrhea or chlamydia, then you might need to avoid having sex during and immediately after treatment. Your Nurx™ medical provider can provide with the exact recommendations for each. How long after antibiotic is birth control effective?If you will be taking antibiotics LONG-TERM, such as for acne, you should use the second method of birth control for at least two weeks after starting the antibiotic.
Do antibiotics stop birth control from working?Most antibiotics do not affect contraception. It's now thought that the only types of antibiotic that interact with hormonal contraception and make it less effective are rifampicin-like antibiotics. These can be used to treat or prevent diseases, including tuberculosis and meningitis.
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