Can Antibiotics Affect Fertility? What to Know When Trying to Conceive
Trying for a baby while you are on antibiotics raises practical questions about timing, safety, and what to do if an infection pops up just as you reach your fertile window. Most short courses of antibiotics do not harm fertility, and many are safe in early pregnancy. The bigger risk usually comes from the infection itself. Untreated urinary tract infections, sexually transmitted infections, or pelvic inflammatory disease can affect your chance of conceiving and can cause complications in pregnancy. Planning ahead helps. Talk with your GP about your current medicines, check whether you need tests for infections, and work out a plan for cycle tracking. Support your gut health with balanced food and consider probiotics if antibiotics upset your digestion. If you need treatment now, ask which options are suitable when trying to conceive and what to do if you get a positive pregnancy test mid course.
Quick Answers About Planning for Conception Whilst on Antibiotics
Do antibiotics stop you getting pregnant? Most do not. They do not switch off ovulation or block fertilisation. The main concern is the infection you are treating. Fever, severe illness, and pelvic infections can delay ovulation or damage the fallopian tubes if untreated.
Are antibiotics safe in early pregnancy? Many are. Penicillins and cephalosporins are commonly used. Some medicines are avoided or timed with care, such as tetracyclines, quinolones, and trimethoprim in the first trimester. Your prescriber will balance benefits and risks using Australian guidance.
Do antibiotics affect the pill? Only rifampicin and rifabutin reduce the effectiveness of hormonal contraception through liver enzyme induction. Use condoms and consider a non hormonal backup during treatment and for 28 days after the last dose. Other antibiotics do not reduce pill effectiveness.
What planning for conception while on antibiotics involves
Planning starts with a clear picture of your health, your cycle, and your medicines. Share all prescription and over the counter products with your GP, including topical creams and acne treatments that contain antibiotics. Ask whether to complete the current course before trying for a baby or whether you can continue trying as planned.
If you are not already taking folic acid, start at least one month before conception and keep going through the first trimester. Most people need 400 micrograms daily, though some need a higher dose because of medical history. Your GP can guide the right amount.
Map your cycle so you know when you usually ovulate. If you are on antibiotics for a short time, you can still try in the same cycle if you feel well, unless your doctor advises otherwise for an infection that requires sexual abstinence during treatment. If you test positive for pregnancy while on antibiotics, call your GP promptly so your treatment can be confirmed as suitable for early pregnancy.
Do antibiotics affect fertility and menstrual cycles
Most antibiotics do not reduce egg quality or stop ovulation. Cycle timing can shift if you have a fever, poor appetite, or sleep disruption. Illness places stress on the body and ovulation can occur later than usual. If you are using ovulation predictor kits, you may see a delayed surge in luteinising hormone after an illness.
Untreated infection is a larger threat to fertility. Chlamydia and gonorrhoea can progress to pelvic inflammatory disease, which can scar the fallopian tubes. Early diagnosis and targeted antibiotics protect future fertility. See a GP for screening if you have risk factors or symptoms.
For male partners, some antibiotics can temporarily lower sperm count or reduce motility. This change usually reverses within about three months, in line with the sperm production cycle. If you are worried, ask whether other treatments are suitable and consider a repeat semen analysis after recovery.
Infections, treatment, and pregnancy safety in Australia
Antibiotics treat bacterial infections. They do not treat viruses or fungal infections. Using antibiotics only when needed helps prevent resistance and protects options for future care. In pregnancy and while trying to conceive, the benefits of treating a confirmed bacterial infection usually outweigh potential medicine risks, especially when the infection could spread or cause complications.
In Australia, prescribers use Therapeutic Goods Administration pregnancy categories and clinical guidelines to select suitable medicines for each stage of pregnancy. Penicillins such as amoxicillin and ampicillin, and cephalosporins such as cephalexin, are commonly used if needed. Erythromycin and clindamycin are also used when appropriate. Some medicines are avoided or timed with care. Tetracyclines such as doxycycline and minocycline are avoided in pregnancy. Quinolones such as ciprofloxacin are usually avoided unless alternatives are not suitable. Trimethoprim, a folate antagonist, is avoided in the first trimester. Nitrofurantoin is a standard option for urinary tract infection in early and mid pregnancy but is usually avoided near term and in people with risks for red cell conditions.
Work with your GP to match the antibiotic to the infection, the timing in your cycle or pregnancy, and any other health factors. Do not stop antibiotics early without medical advice.
How infections are diagnosed and what the tests involve
Your GP will start with a history and a physical examination to pinpoint symptoms and risk factors. For urinary symptoms, you will provide a clean catch urine sample for a dipstick and culture. For vaginal discharge, pain, or bleeding, your GP may take a self collected or clinician collected vaginal swab to test for bacterial overgrowth and sexually transmitted infections. For suspected chlamydia or gonorrhoea, a urine test or swab is used.
If pelvic inflammatory disease is suspected, examination may include abdominal and pelvic assessment and, where indicated, a pelvic ultrasound. Blood tests may check markers of inflammation and pregnancy status. Pregnancy testing helps guide antibiotic selection if periods are late or there is a chance of early pregnancy.
Results guide targeted treatment, partner management, and follow up testing. Most tests are simple, quick, and covered in standard primary care pathways. Your GP will explain what to expect and how results will be delivered.
Home care while taking antibiotics and trying to conceive
Take antibiotics exactly as prescribed and finish the course. Read the label for food instructions. Some medicines are best with food to reduce nausea. Drink water regularly and rest. If your antibiotic interacts with alcohol, for example metronidazole, avoid alcohol completely during the course and for the advised time after the last dose.
Support your gut with fibre rich foods such as vegetables, whole grains, and legumes. Many people find that live cultured yoghurt or a probiotic helps with loose stools during and after antibiotics. If you choose a probiotic, take it at a different time of day to your antibiotic.
Sexual activity during treatment depends on the infection. If you are being treated for a sexually transmitted infection, avoid sex until you and your partner have completed treatment and any test of cure. For urinary tract infection without STI risk, sex is fine when you feel comfortable. If you develop a rash, breathing problems, severe diarrhoea, or ongoing vomiting, stop the medicine and seek urgent care.
When to see a GP or fertility specialist in Australia
See your GP if you have burning when you pass urine, pelvic pain, abnormal discharge, fever, or new bleeding. Early testing and treatment protect fertility and reduce pregnancy risks. Seek care quickly if you notice severe lower abdominal pain, high fever, vomiting, or signs of allergic reaction such as wheeze, swelling, or hives.
If you have had pelvic inflammatory disease, chlamydia, or gonorrhoea in the past, a preconception check is sensible. Ask about screening for reinfection and whether you need an assessment of tubal factors. If you have been trying to conceive for twelve months, or for six months if you are thirty five or older, ask for a referral to a fertility specialist. People with irregular cycles, known endometriosis, or two or more miscarriages can be referred sooner.
For medicine questions, your pharmacist can review interactions and give advice on timing with food, probiotics, or other supplements. If you use hormonal contraception and are prescribed rifampicin or rifabutin, ask about extra protection.
Where ovulation and pregnancy tests fit into the plan
Ovulation predictor kits measure the rise in luteinising hormone in urine. Antibiotics do not interfere with this hormone signal. Illness can delay the surge, so keep testing daily if you are unwell and your usual timing shifts. If you start an antibiotic course just before your fertile window, you can still try to conceive if the infection is not sexually transmitted and you feel well. Your GP can advise if abstinence is needed for an STI.
Home pregnancy tests measure human chorionic gonadotropin in urine. Antibiotics do not cause false positive or false negative results. The main exceptions are fertility injections that contain hCG. Test about two weeks after ovulation or from the day your period is late. Test first thing in the morning if you are early in the luteal phase, as urine is more concentrated. If you get a positive result while taking antibiotics, contact your GP to confirm that your treatment suits early pregnancy.
Frequently Asked Questions About Planning for Conception Whilst on Antibiotics Australia
Can I try to conceive while taking antibiotics for a urinary tract infection? You can in many cases. If you feel well and your GP has chosen a pregnancy suitable antibiotic, there is usually no need to delay. Some people prefer to wait until symptoms settle. If you suspect pregnancy, let your GP know before the prescription is finalised.
Should I delay trying to conceive until I finish antibiotics? It depends on the infection, the medicine, and how you feel. For sexually transmitted infections, wait until you and your partner complete treatment and any follow up testing. For other infections, many people keep trying once they feel comfortable. Ask your GP for advice for your situation.
Is nitrofurantoin safe when trying to conceive? Nitrofurantoin is widely used for urinary tract infection and is considered suitable in early and mid pregnancy. It is usually avoided near term and in some red blood cell conditions. Your GP will weigh benefits and risks and can offer an alternative if it does not suit you.
Could antibiotics cause miscarriage? Research shows mixed findings for some antibiotics in early pregnancy, and illness itself can raise risk. Doctors in Australia choose well studied options that are considered suitable in pregnancy when treatment is needed. Do not stop a prescribed course without advice. If you are worried, ask your GP to review your options.
Do probiotics help while I am on antibiotics? Many people find probiotics reduce antibiotic associated diarrhoea and help gut balance. Choose a product with clear strain information and take it at a different time of day to the antibiotic. Fibre rich foods such as vegetables, fruit, and whole grains also support gut health.
What about long term antibiotics for acne when trying to conceive? Long term oral antibiotics for acne may not be ideal when trying to conceive, especially tetracyclines, which are avoided in pregnancy. Ask your GP or dermatologist about non antibiotic options or topical treatments that suit preconception and pregnancy plans.
Moving forward with confidence
Most people can keep trying for a baby while on a short course of antibiotics, with guidance tailored to the infection and the medicine used. If you need treatment now, focus on getting well, then return to your plan with cycle tracking. If you are taking long term antibiotics, ask whether a drug holiday or an alternative is appropriate when you reach your fertile window. If you have a history of pelvic infection, consider a preconception check and screening for reinfection.
Cycle tools help you time intercourse and reduce guesswork. Ovulation tests identify your most fertile days, and early response pregnancy tests can confirm a result from the day your period is due. Antibiotics do not affect these tests, so you can keep using them as planned. If a test turns positive mid course, book a prompt GP review. With clear information, local care, and a simple plan, you can protect your health while giving yourself the best chance of pregnancy.
References
https://www.healthdirect.gov.au/antibiotics
https://www.healthdirect.gov.au/pregnancy-and-medicines
https://www.healthdirect.gov.au/urinary-tract-infection-uti
https://www.healthdirect.gov.au/chlamydia
https://www.healthdirect.gov.au/pelvic-inflammatory-disease
https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/antibiotics
https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/pregnancy-and-medicines
https://www.tga.gov.au/pregnancy-category-database
https://www.fpnsw.org.au/factsheets/individuals/contraception/antibiotics-and-contraception
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.
