Why do antibiotics affect the pill

If you don't ovulate at all, you can't get pregnant. Keep sperm from making it to the uterus. Birth control can do this by causing your cervical mucusyou've probably heard this referred to as "vaginal discharge" to get thicker.

Thicker cervical mucus makes it incredibly hard for sperm to swim to an egg. Make implantation unlikely. Hormonal birth control can make changes to your uterus lining that decrease the chances of a fertilized egg being implanted. Even if a sperm somehow makes it to an egg to fertilize it, you only get pregnant if it successfully implants in your uterine lining. No implantation, no pregnancy.

Rifampin can keep your birth control from doing its job by causing your liver to break down estrogen faster than it usually would. When estrogen gets broken down too quickly, it can't drive the changes in your body that normally keep you from getting pregnant.

Note: Copper IUDs don't use hormones to prevent pregnancy, so they won't be affected by any medicine that may change your hormone levels.

Rifampin may be the only antibiotic proven to lower the effectiveness of hormonal birth control, but it's not the only drug that can do so. These medicines can also increase your chances of getting pregnant while taking hormonal birth control:.

Some protease inhibitors used to treat HIV. Certain anti-seizure medications. Griseofulvin, an antifungal medication. The length of time that antibiotics or other drugs can affect birth control depends on which medicine you're taking. Some medications will only affect hormone levels while you're taking them.

Others can have effects that linger for up to a week or even a month after you stop taking the medicine. If you're prescribed something that makes your birth control less effective, your doctor will be able to tell you how long you should use a backup method of birth control. If you're worried that the medication you're taking may be affecting your birth control, you can always use a backup method to help prevent pregnancy, such as:. Diaphragms and cervical caps: With typical use, prevents pregnancy in 83 out of women.

Sponges: With typical use, prevents pregnancy in 63 to 86 out of women, depending on whether or not they've already had a baby. Drug interactions are complicated, so it's always best to talk to your doctor about all prescriptions, over-the-counter drugs, and supplements you're taking before you start any new treatment. If you start taking medicine that makes your hormonal birth control less effective, you may need to add a backup method, such as condoms, to prevent pregnancy.

Aside from rifampin, most antibiotics shouldn't affect whether your birth control works or not. Estrogen helps prevent ovulation and subsequent conception from occurring.

The liver processes everything a person puts into their body, including the hormones in birth control pills, birth control patches, birth control rings, and other medications. An unintended pregnancy can result from this process. The estrogens in the birth control pill, when broken down in the liver, are then converted into other chemicals.

These converted chemicals are secreted out of the liver in the form of bile and are absorbed by the intestines. Gut flora in the intestines then turn these chemicals back into active estrogen. Finally, the body reabsorbs the active estrogen from the intestines. The process of estrogen recirculation is called entero-hepatic cycling. The way antibiotics work is that they kill off any bad bacteria that is causing an infection. The human body is made up of billions of different types of beneficial bacteria that play a key, integral role in many different biochemical processes.

A number of these good bacteria colonize the intestinal tract. When someone takes antibiotics, these gut bacteria get killed off too, in addition to the bacteria that are causing an infection. Testicular torsion refers to the twisting of a testicle and the spermatic cord attached to it, inside the scrotum. If prolonged and untreated, the twisting rapidly affects the [ How to treat Psoriasis What is Psoriasis?

Psoriasis is a chronic long term skin condition that causes areas of the skin to become thickened, red, and scaly described as [ The causes of breast pain Breast pain refers to any area or areas of tenderness, discomfort or pain in one or both breasts. You may be asked to take this contraception in a different way from usual and use condoms as well.

One option for women who have a contraceptive implant and need to take a short dose of rifampicin for preventing meningitis, for example is a single dose of the progestogen injection.

You and your doctor can get up-to-date guidance about contraception and antibiotics from the Faculty of Sexual and Reproductive Healthcare. You do not normally need to use additional contraception if you're taking antibiotics other than rifampicin and rifabutin.

But if the antibiotics or the illness they're treating cause diarrhoea or vomiting, absorption of the contraceptive pill may be affected. For more information, see What if I'm on the pill and I'm sick or have diarrhoea? Page last reviewed: 28 January Next review due: 28 January Will antibiotics stop my contraception working? Where to get contraception. What is emergency contraception? Where can I get emergency contraception? Emergency contraception.