Can Antibiotics Affect Fertility?

“There is some evidence that certain antibiotics can influence reproductive function, but the effects vary widely depending on the medication and the situation,” says Lisa Marii Cookingham, MD, a clinical assistant professor and medical director of the Fertility Preservation Program at The University of North Carolina School of Medicine in Chapel Hill.

Fertility experts don’t consider antibiotic use a huge risk for people who are trying to have a baby. And Dr. Cookingham says that this group of people is not advised to avoid antibiotics when doctors deem them medically necessary.

Here’s what to know about the relationship between antibiotic use and fertility, which classes of these drugs aren’t compatible with pregnancy, and when you’re better off taking them.

“I am more concerned about women reading [about] this and being scared to use necessary antibiotics,” says Veronica Vernon, PharmD, chair and associate professor of pharmacy practice at Butler University of College of Pharmacy in Indianapolis. “There are very real and significant health risks if someone does not treat a bacterial infection.”

She also points out that some of the studies analyzed didn’t examine why the participants were taking antibiotics or what other fertility concerns they may have had before taking them. ”If individuals were being treated for sexually transmitted infections (STIs), it is more likely that the STIs led to fertility concerns and not antibiotic use,” she says.

“[Antibiotics] alter the gut and vaginal microbiome, which can influence hormone metabolism, including how estrogen is processed in the body,” says Cookingham. “Some antibiotics may also affect inflammatory pathways that are important for embryo implantation, but these effects are not universal, and many antibiotics appear neutral or even protective in some studies.”

• Beta-lactams, such as penicillins, cephalosporins, beta-lactamase inhibitors, and carbapenems
• Glycopeptides and lipopeptides, such as vancomycin and daptomycin
• Lincosamides, such as clindamycin

• Animoglycosides, which pose a risk of irreversible deafness in the fetus
• Fluoroquinolones, which can cause kidney, heart, and central nervous system issues in the fetus
• Lipoglycopeptides, which increase the risk of developmental defects
• Macrolides and sulfonamides, which are linked to birth defects and pregnancy loss
• Tetracyclines, which may harm the fetus and cause tooth discoloration

Antibiotics should always be taken under a doctor’s care. If you think you might have an infection and are trying to become pregnant, see your doctor. The doctor will do the necessary tests to figure out if you need antibiotics and which ones might be best for you.

“It depends on how and when you’re using it, but men’s sperm regenerate every two and a half to three months, so any negative effects would only be temporary,” says Bradley Trivax, MD, a reproductive endocrinology and infertility specialist at Stony Brook Medicine's Island Fertility in Commack, New York.

Cookingham agrees that in most cases, antibiotics do not cause permanent harm to male fertility, and infections themselves can negatively impact future fertility if left untreated.

“Untreated infections can pose serious risks to both fertility and pregnancy, including miscarriage, preterm birth, and other complications,” says Cookingham. “Treating infections remains an important part of optimizing reproductive health.”

For most people, simply be judicious about when and why you take antibiotics — advice that holds true for all people, not only those who are trying to conceive. “Don’t run to your physician every time you have a cold thinking you need antibiotics,” says Robert Atlas, MD, chair of the department of obstetrics and gynecology at Mercy Medical Center in Baltimore. “Most of those symptoms are viral in nature, and antibiotics don’t treat that. However, if you do have a bacterial infection, antibiotics will be required.”

• Research suggests that taking certain types of antibiotics may negatively affect fertility when taken in the weeks or months before pregnancy. However, fertility experts don’t consider this a major cause for concern for couples who are trying to conceive.
• Untreated infections, particularly those that were sexually transmitted, may pose far greater risks to fertility and pregnancy than the medications used to treat them.
• Always speak to your doctor before taking any medications. Also, try to use antibiotics judiciously, and not for viral infections in which they won’t be effective.