The question of whether antibiotics can affect fertility is increasingly common among those trying to conceive, but the relationship is complex. While certain antibiotics may impact reproductive health, experts emphasize that the risks are often overstated, and untreated infections pose a greater threat. Here’s a clear breakdown of the current understanding.
The Link Between Antibiotics and Fertility
Recent research suggests that antibiotic use in the months leading up to conception could slightly increase the risk of infertility, miscarriage, and birth defects. Studies have identified specific classes – macrolides, sulfonamides, and trimethoprim – as potentially problematic. However, experts caution against unnecessary alarm.
“The bigger danger is people avoiding crucial antibiotics when they actually need them,” says Veronica Vernon, PharmD, chair of pharmacy practice at Butler University. Untreated bacterial infections can be far more damaging than temporary antibiotic exposure.
How Antibiotics May Affect the Body
Antibiotics can disrupt the vaginal microbiome, which plays a role in hormone regulation and embryo implantation. Altering the balance of microorganisms can impact estrogen processing and inflammatory pathways. However, studies show that many antibiotics have neutral or even protective effects.
Moreover, male fertility is also subject to temporary fluctuations. While sperm can be affected, the body regenerates sperm every 2.5-3 months, mitigating long-term damage.
Which Antibiotics to Avoid (and Which Are Safe)
Certain antibiotics carry higher risks during pregnancy or conception attempts:
- Avoid: Aminoglycosides (potential deafness in the fetus), fluoroquinolones (kidney/heart/CNS issues), lipoglycopeptides (developmental defects), tetracyclines (fetal harm/tooth discoloration).
- Generally Safe: Beta-lactams (penicillins, cephalosporins), glycopeptides/lipopeptides (vancomycin, daptomycin), lincosamides (clindamycin).
Always consult a doctor before taking any medication, especially if you’re trying to conceive.
When Antibiotics Can Help Fertility
Untreated bacterial infections – such as pelvic inflammatory disease (PID), bacterial vaginosis, and chronic endometritis – can directly impair fertility. In these cases, antibiotics are vital for resolving the infection and improving conception chances.
Sexually transmitted infections (STIs) are particularly concerning: untreated bacterial STIs can lead to PID, a severe infection of the reproductive organs.
The Bigger Picture: Judicious Use is Key
The core message is balance. Antibiotics are essential when medically necessary, but overuse is harmful regardless of reproductive status. As Robert Atlas, MD, of Mercy Medical Center, advises: “Don’t run to your physician for every cold. Antibiotics treat bacterial infections, not viruses.”
Ultimately, the greatest risk isn’t antibiotics themselves, but untreated infections. When used responsibly under medical guidance, antibiotics pose a manageable risk, while ignoring bacterial infections can have severe and lasting consequences.
