Trying to Conceive While on Antibiotics

When you are ready to conceive, you should do everything possible to increase your chances of becoming pregnant. A variety of factors may impact fertility, including age, weight, and whether or not you use alcohol or smoke. Some medications you take may influence your likelihood of becoming pregnant. Antibiotics may either promote or inhibit conception , depending on the circumstances. Before trying to conceive, examine your medicine cabinet and inform your doctor of any antibiotics or other medications you use.

Gut Microbiome and Estrogen Metabolism

Antibiotics treat infections but can disrupt the gut microbiome’s balance. The enzyme β‑glucuronidase, produced by beneficial gut bacteria, maintains hormonal balance by deconjugating estrogen compounds, allowing their reabsorption and recycling. Antibiotic use reduces these bacteria, lowering β‑glucuronidase activity, which can alter estrogen levels and affect reproductive health.

A fibre-rich diet and naturally fermented foods support a healthy gut, and probiotic supplements may help maintain enzyme activity. This balance is crucial for those planning to conceive, as stable estrogen recycling regulates menstrual cycles and creates a supportive environment for pregnancy.

Various infections

It is essential to understand that there are several types of infections, such as bacterial, fungal, and viral infections. Antibiotics only cure illnesses caused by bacteria. They are not given for viral or other non-bacterial diseases since they are ineffective against these pathogens. It is vital not to take unnecessary or ineffective antibiotics since this may contribute to developing drug-resistant bacteria, rendering medications ineffective when required. Non-bacterial infections may be treatable with other medications. However, antibiotics may be quite successful if you have a bacterial illness that requires treatment.

Illnesses caused by bacteria during pregnancy

During pregnancy, common bacterial illnesses include urinary tract infections (UTIs) and group B strep. Antibiotics are the only effective treatment for many illnesses. Therefore, you should take them despite their danger to your unborn child. Why? According to Komal Bajaj, M.D ., MS-HPEd, an OB-GYN, reproductive geneticist, and Chief Quality Officer at NYC Health + Hospitals/Jacobi in New York City, leaving an infection untreated might pose a greater danger to your baby’s health than exposing them to an antibiotic. Your prenatal care provider will know which medicines should be avoided during pregnancy and will be educated to administer drugs with superior safety records.

Why Antibiotics Enhance Fertility

Bacterial infections are one of the most prevalent causes of infertility in both men and women. Sexually transmitted diseases (STIs) such as chlamydia and gonorrhoea may harm a woman’s uterus, ovaries, and fallopian tubes and a man’s sperm tubes. Occasionally, these infections might not produce symptoms. You may be unaware that you have an STI. Bacteria may travel to the uterus, ovaries, and fallopian tubes and develop pelvic inflammatory disease if not treated. PID may result in scarring of the fallopian tubes. These scars may hinder an egg from passing through the tubes to be fertilised. Doctors prescribe antibiotics to treat bacterial illnesses. Treating these illnesses may avoid harm to the reproductive system and increase the likelihood of conception.

How Antibiotics Make Pregnancy Difficult

Long-term usage of some antibiotics is associated with infertility issues in males. Antibiotics have both a quantitative and qualitative effect on sperm. They may diminish the amount of sperm a man makes and delay the swimming speed of the sperm he does generate. These antibiotics have the potential to influence sperm quantity and movement :

• Erythromycin
• Gentamicin (Garamycin)
• Neomycin
• Nitrofurantoin (Macrobid)
• Tetracyclines

The effects on fertility should cease after three months of stopping antibiotic treatment. However, if you are concerned, you may ask your doctor to prescribe an antibiotic that will not alter sperm quality.

Can antibiotics reduce the effectiveness of birth control?

A few antibiotics may create complications for those who do not want to get pregnant. Rifampicin (Rifadin) and rifabutin (Mycobutin) can interact with birth control tablets and reduce efficacy. Antibiotics are prescribed to treat meningitis and TB. The majority of alternative antibiotics will not produce this adverse effect. Whether you must take Rifadin or Mycobutin, ask your doctor if you should use condoms or another contraception to avoid pregnancy.

Antibiotics and Miscarriage Risk

Recent studies show a link between certain antibiotics—such as azithromycin, clarithromycin, metronidazole, some quinolones, sulfonamides, and tetracyclines—and an increased risk of miscarriage. However, these findings indicate correlations, not causation. Key points include:

• Research correlations do not prove that these antibiotics directly cause miscarriage.
• The associations might result from the severity of bacterial infections needing treatment, not the medications themselves.
• Differences in study designs, treatment timing, and patient health can influence outcomes, making a direct cause-and-effect relationship hard to establish.
• Not all studies consistently find these links, so the data should be interpreted cautiously.

Consulting a healthcare provider is essential to determine the safest treatment for both mother and baby.

Antibiotics: Both safe and harmful during pregnancy

The following antibiotics (but not limited to these) are usually regarded as SAFE for usage during pregnancy:

• Amoxicillin
• Ampicillin
• Augmentin
• Penicillin
• Cephalexin
• Clindamycin
• Erythromycin

The following antibiotics (but not limited to these) are usually regarded as UNSAFE for usage during pregnancy:

• Bactrim: Interferes with folate metabolism, which can increase the risk of neural tube defects and other structural congenital disabilities.
• Ciprofloxacin: Animal studies suggest it may damage developing cartilage, potentially impairing joint formation and overall skeletal development.
• Doxycycline: Known to affect bone growth and cause permanent tooth discoloration, posing risks for proper dental and skeletal formation.
• Furadantin, Macrobid, and Macrodantin (nitrofurantoin formulations): These medications have been associated with potential liver toxicity and neonatal hemolytic anemia, particularly in genetically susceptible infants.
• Minocycline and Tetracycline: Their ability to bind with calcium can inhibit normal bone development and lead to permanent tooth discoloration.
• Septra: With effects similar to Bactrim, it may disrupt folate metabolism and increase the chance of congenital malformations.

Clarithromycin and azithromycin exposure during pregnancy

In a study published in the journal Pharmacoepidemiology and Drug Safety , researchers evaluated whether using macrolide antibiotics, such as azithromycin and clarithromycin, during pregnancy was associated with having a child with a congenital abnormality. Using data from nearly 135,000 pregnant women in the Quebec Pregnancy Cohort (nonbinary persons were not included in this data), researchers examined the results of those who had taken macrolides, penicillin, and no antibiotics. The study’s author, Anick Bérard, PhD, a professor at the University of Montreal’s Faculty of Pharmacy and a researcher at the hospital’s associated CHU Sainte-Justine, found no statistically significant link between the usage of macrolides during pregnancy and the risk of abnormalities.

Antibiotics and Pregnancy

This is encouraging for treating infections in pregnant women. The FDA defines azithromycin as a Category B medicine, indicating that animal tests have shown it to be safe. Clarithromycin is classified as Category C, which indicates that adverse effects on animals have been documented. Neither group has been the subject of well-controlled human research. However, data is being gathered to monitor for a rise in the prevalence of congenital abnormalities in children born to mothers who took the medicines during pregnancy. Even though many drugs are entirely safe to use during pregnancy, some might cause severe foetal issues. The Food and Drug Administration’s (FDA) list of Pharmaceutical Pregnancy Categories informs doctors (and patients) about the safety of drugs during pregnancy. There are five categories: A, B, C, D, and X . Here is a breakdown of what the various categories imply.

• Category A: Proven safe for pregnant women.
• Category B: Animal studies failed to demonstrate foetal toxicity; no appropriate human investigations exist.
• Category C: Animal studies indicate detrimental effects on the foetus, or no animal or human research is available.
• Category D: Animal studies indicate a positive risk to the foetus in category D, although the benefits may exceed the hazards.
• Category X: Animal studies demonstrate a definite danger but no benefits.

Medication Safety Categories During Pregnancy

Medications during pregnancy are classified to ensure their safe use. Here’s a simplified overview of these categories:

• Category A: Medications with strong evidence from human studies confirming their safety during pregnancy.
• Category B: Drugs generally considered safe; animal studies show minimal risk, though robust human data may be limited.
• Category C: Medications where animal studies indicate possible risks. Use only if the expected benefits justify potential hazards.
• Category D: Drugs linked to fetal risk in human studies. Use only when benefits significantly outweigh the risks.
• Category X: Medications with clear risks that outweigh any potential benefits. They should be avoided.

Always consult your healthcare provider about any medications to ensure safety for you and your baby.

The truth about medication safety categories

Ethical issues prohibit performing pharmacological trials on pregnant women. Hence, sufficient and well-controlled studies have not been conducted on many treatments, according to Dr Fuks. For instance, there may be unidentified adverse foetal consequences connected with some medications under Category B. “[Medications] should only be provided when the health care professional firmly thinks that the benefits exceed the dangers to the baby and pregnancy,” Dr Fuks advises. Although many medicines, such as penicillin, have been used safely for decades, antibiotic-resistant bacterial strains are prompting doctors to utilise more antibiotics. The safety of an antibiotic relies on many variables, including the kind of antibiotic, when it is used during pregnancy, the dose, and the length of usage.

Putting heightened risks in the context

Even though antibiotics have been linked to an increased risk of congenital abnormalities, the likelihood is still modest. For instance, the probability of conceiving a kid with hypoplastic left heart syndrome is around 1 in 4,200. According to the National Center on Birth Defects and Developmental Disabilities, sulfonamide antibiotics such as Septrin (co-trimoxazole) and Bactrim (sulfamethoxazole/trimethoprim) are connected with a threefold rise, making the risk around one in 1,400.

Final thoughts

If you are attempting to conceive or are pregnant, see your doctor before taking antibiotics or any other new medication, including over-the-counter medications. If a necessary medication might damage your fertility or pregnancy, your doctor may be able to recommend an alternative.

Evan kurzyp

Evan Kurzyp

Evan is the founder of Fertility2Family and is passionate about fertility education & providing affordable products to help people in their fertility journey. Evan is a qualified Registered Nurse and has expertise in guiding & managing patients through their fertility journeys.