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Do Antibiotics Affect Fertility?

Reviewed by Nivin Todd, MD on August 17, 2020

When you're ready to conceive, you want to do everything you can to improve your odds of a pregnancy. A number of things can affect your fertility, including your age, your weight, and whether you drink alcohol or smoke.

Some of the medicines you take could also affect your odds of a pregnancy. Antibiotics can either help or hurt your fertility, depending on your situation.

Check your medicine cabinet and talk to your doctor about any antibiotics or other medicines you take before you try to conceive.

How Antibiotics Improve Fertility

Bacterial infections are one of the most common causes of infertility in both men and women. Sexually transmitted infections (STIs) like chlamydia and gonorrhea can damage the uterus, ovaries, and fallopian tubes in women, and the tubes that sperm travel through in men.

Sometimes these infections don't cause symptoms. You may not even know you have an STI. Without treatment, bacteria can spread to the uterus, ovaries, or fallopian tubes and cause pelvic inflammatory disease (PID).

Continued

PID can leave scars in the fallopian tubes. Those scars might block the tubes and prevent an egg from traveling down them to be fertilized.

Doctors prescribe antibiotics to treat bacterial infections. Treating these infections can prevent damage to the reproductive tract and may improve the odds of a pregnancy.

How Antibiotics Make It Harder to Get Pregnant

Some antibiotics cause fertility problems in men who take them for a long time. Antibiotics affect both the quantity and quality of sperm. They may reduce the number of sperm a man produces, and make the sperm he does produce swim more slowly.

These are some of the antibiotics that could affect sperm quantity and movement:

The effects on fertility should stop within 3 months after you stop taking antibiotics. But if you're worried, ask your doctor to prescribe an antibiotic that won't affect sperm quality.

Can Antibiotics Make Birth Control Less Effective?

A few antibiotics might cause problems for people who don't want to get pregnant. Rifampicin (Rifadin) and rifabutin (Mycobutin) can interact with birth control pills and make them less effective. Doctors prescribe these antibiotics to treat meningitis and tuberculosis.

Most other antibiotics won't cause this side effect. If you need to take Rifadin or Mycobutin, ask your doctor if you should use condoms or another type of birth control to prevent an unplanned pregnancy.

Antibiotics and Miscarriage Risk

One large study linked the use of antibiotics with an increased risk for miscarriage. The drugs that seemed to increase this risk were:

This study didn't prove that antibiotics cause miscarriage. A few other studies have found the same link, but others haven't. Also, the authors couldn't tell whether it was the antibiotics, or the infections those antibiotics were treating that led to the miscarriages.

Antibiotics and Pregnancy

If you are trying to get pregnant or you're already pregnant, check with your doctor before you take antibiotics or any other new medicines, including over-the-counter medicines. If a medicine you need could affect your fertility or pregnancy, your doctor might be able to prescribe something else.

WebMD Medical Reference

Sources

SOURCES:

American Journal of Obstetrics & Gynecology: "Sexually Transmitted Diseases and Infertility."

CMAJ: "Use of antibiotics during pregnancy and risk of spontaneous abortion."

Fertility Coalition: "Sexually transmitted infections (STIs)."

Fertility Network UK: "Factors Affecting Fertility."

Harvard Medical School: "Making fertility-friendly lifestyle choices."

Intech Open: "Staphylococcal Infection and Infertility."

Journal of Genital System & Disorders: "Antibiotic Therapy as Infertility Management."

NHS: "How can I improve my chances of becoming a dad?" "Will antibiotics stop my contraception working?"

The American College of Obstetricians and Gynecologists: "Pelvic Inflammatory Disease (PID)."

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