Taking antibiotics while trying to conceive does not automatically mean you need to stop trying. Many people can continue during a short course, but the answer depends on the exact medicine, the infection being treated, who is taking it and whether pregnancy is already possible.
Antibiotics are not contraceptives, but they are not one interchangeable group. Taking an antibiotic does not by itself show that fertility has been reduced, ovulation delayed, implantation prevented or an early pregnancy harmed. The active ingredient, dose, route, treatment length and reason for treatment all affect the advice.
The infection can matter as much as the medicine. Urinary tract infections need prompt treatment, while untreated chlamydia, gonorrhoea and pelvic inflammatory disease can affect reproductive health. Do not stop early, miss doses or create your own break around ovulation. Tell your GP or pharmacist that you are trying to conceive and whether you are before ovulation, in the two-week wait or late for a period.
Quick Answers About Trying to Conceive While Taking Antibiotics
Can you get pregnant while taking antibiotics for a UTI?
Yes. Antibiotics do not prevent pregnancy. Trying can often continue when the prescribed medicine is appropriate if pregnancy is possible, the infection does not require a temporary pause from sex and you feel well enough. This commonly includes treatment for a straightforward UTI after the prescriber has considered the possibility of pregnancy.
My husband or male partner was taking antibiotics when we conceived. Should I be worried?
Medicine taken by a male partner does not expose an embryo in the same way as medicine taken by the person who becomes pregnant. A brief routine course is not usually a reason to assume conception was unsafe. Prolonged treatment, repeated courses, high fever, an STI or an infection involving the testes, epididymis or prostate needs individual advice.
How long should I wait after antibiotics before trying to conceive?
There is no waiting period that applies to every antibiotic. Some couples can continue trying during treatment. A temporary pause may be advised for an STI, severe illness, a medicine that needs pregnancy-specific review or cycle-specific instructions from a fertility clinic.
What Decides Whether You Can Keep Trying?
Whether to keep trying depends on five practical details: who is taking the medicine, the active ingredient, the infection, where you are in the cycle and how unwell you are.
| What to check | Why it changes the advice |
|---|---|
| Who is taking it? | Medicine taken by the person who may become pregnant is assessed differently from medicine taken by the male partner. |
| Which active ingredient? | Amoxicillin, nitrofurantoin, trimethoprim, doxycycline, azithromycin and ciprofloxacin do not have the same pregnancy information. |
| Which infection? | An uncomplicated bladder infection differs from an STI, pelvic infection, kidney infection or illness affecting the whole body. |
| Where are you in the cycle? | The prescriber needs to know whether you are before ovulation, in the two-week wait, late for a period or already have a positive pregnancy test. |
| How unwell are you? | Fever, vomiting, dehydration, severe pain or a worsening infection may make treatment and recovery the immediate priority. |
Check the active ingredient, dose, route and treatment length rather than relying only on a brand name. Australian pregnancy categories are not ranked from safest to least safe. The prescriber also considers the reason for treatment, pregnancy timing, available evidence and the risk of leaving the infection untreated.
Do Antibiotics Affect Fertility, Ovulation or Implantation?
There is no single fertility effect shared by every antibiotic. A short course for an acute infection is not evidence by itself of damaged egg quality, reduced ovarian reserve, impaired sperm or future infertility. The medicine and the illness need to be considered separately.
Research on conception is mixed. A prospective study of 9,524 pregnancy planners found no appreciable overall association between recent antibiotic use and the chance of conception per cycle. A later Danish prospective study of 9,462 women found an association between recent antibiotic use and a modestly lower chance of conception per cycle. The Danish researchers could not separate the effect of the medicine from the infection being treated. Neither study proves that antibiotics caused a change in fertility.
Ovulation and cycle timing
A changed cycle while you are unwell does not prove that the antibiotic delayed ovulation. Fever, disrupted sleep, reduced food or fluid intake, illness-related stress and normal cycle variation can change when you notice an LH surge or when your period arrives. Fertility2Family’s guide to the
fertile window and ovulation timing
explains other reasons the expected fertile days can move.
If the expected LH surge does not appear, continue testing for longer if the instructions allow, avoid testing with overly diluted urine and use the test at the recommended time. A short LH surge can occur between tests. Fertility2Family’s guide to
explains what a missing result can and cannot show. If a stronger result appears close to your expected period, read what an
may mean.
Ovulation tests detect luteinising hormone. A positive result suggests that ovulation may be approaching, but it does not prove that an egg was released. Fertility2Family’s guide to
when to have sex after an LH surge
explains how a positive result fits into fertile-window timing. If irregular or absent ovulation becomes a repeated pattern, see your GP rather than attributing every changed cycle to antibiotics.
Implantation and the two-week wait
Implantation cannot be confirmed from symptoms or observed directly at home. Antibiotics also do not share one established effect on implantation. When treatment is needed after ovulation, the prescriber considers the active ingredient, dose, infection, possible pregnancy stage and the risk of not treating the infection.
Tell the prescriber the first day of your last period, your usual cycle length, your estimated ovulation date and whether you use fertility medicines. Do not stop treatment because you think implantation may be occurring.
The untreated infection may be the greater concern
Antibiotics do not stimulate ovulation and are not fertility treatment. Their purpose is to treat a bacterial infection.
Untreated chlamydia and gonorrhoea can progress to pelvic inflammatory disease. PID can scar the fallopian tubes and increase the risk of fertility problems and ectopic pregnancy. Avoiding necessary treatment may therefore create more reproductive risk than taking an antibiotic selected for the infection and the possibility of pregnancy.
My Male Partner Is Taking Antibiotics
Medicine taken by the male partner is assessed differently from medicine taken by the person who becomes pregnant. The medicine is not circulating in the body of the person who may become pregnant, so paternal exposure does not affect an embryo in the same way as medicine taken during pregnancy.
A brief routine course is not usually a reason to assume conception was unsafe. Evidence about sperm differs between medicines, and the illness may matter more than the prescription. High fever, serious infection and infections involving the testes, epididymis or prostate may temporarily affect semen quality or sexual function.
There is no universal requirement for every man to wait three months after every antibiotic. Ask for individual advice when the male partner:
- takes antibiotics for weeks or months;
- needs repeated courses;
- has an STI or reproductive-tract infection;
- has had a high fever or serious illness;
- has known abnormal semen results;
- is preparing to provide a sample for IVF, ICSI or insemination.
Where concerns continue, a
is more useful than assuming permanent damage from a prescription.
How Long Should You Wait After Antibiotics?
Trying can often continue when the prescribed medicine is appropriate if pregnancy is possible, the infection is not sexually transmitted and the prescriber has not advised a delay.
A temporary pause may be needed when:
- you or your partner is being treated for an STI;
- partner treatment is not complete;
- you have fever, severe pain, vomiting or dehydration;
- the infection is not improving;
- the medicine needs pregnancy-specific review;
- your fertility clinic gives different instructions.
Consider two common situations. Someone prescribed amoxicillin for a straightforward UTI may be able to keep trying after the prescriber confirms that the medicine is suitable and symptoms are improving. Someone prescribed doxycycline for chlamydia should pause sex until the required treatment period has passed and partners have been treated. The antibiotic name alone does not decide the answer. The infection and treatment instructions matter as well.
Complete the prescribed course unless the treating clinician changes it. Do not save tablets, shorten treatment, skip doses around ovulation or restart leftover antibiotics later.
UTIs, STIs and Pelvic Infection While Trying to Conceive
Urinary tract infections
You can often keep trying to conceive while taking antibiotics for a UTI when the medicine is appropriate if pregnancy is possible, there is no STI concern and sex is comfortable. A UTI still needs prompt assessment. Symptoms can include burning when passing urine, urgency, frequent urination, lower abdominal discomfort, cloudy urine or blood in the urine.
Your GP may request a urine sample and culture so treatment can be matched to the likely bacteria. Tell the GP or pharmacist if pregnancy is possible or confirmed, as this can change the assessment and antibiotic choice. Seek urgent review for fever, chills, back or side pain, vomiting, worsening symptoms or feeling very unwell, as these can occur with a kidney infection.
Sexually transmitted infections
Trying to conceive should pause when an STI requires both partners to be treated and sexual contact to stop temporarily. For chlamydia, follow the treating service’s instructions about completing treatment, symptom resolution, partner treatment and when sex can resume. Australian guidance advises avoiding sex until at least seven days after treatment started, or until the course is finished and symptoms have resolved, whichever is later. Recent partners also need assessment and treatment to reduce the risk of reinfection.
Pelvic pain, abnormal discharge, bleeding between periods, pain during sex or fever may require assessment for PID. Severe pain, vomiting, faintness or possible pregnancy needs urgent review because these symptoms can overlap with ectopic pregnancy and other urgent conditions.
Common Antibiotics Used in Australia
The table below explains why medicine-specific advice matters. It is not a guide for choosing, stopping, swapping or restarting treatment yourself. Current Consumer Medicine Information, the reason for treatment and the prescriber’s assessment take priority.
| Medicine or group | What matters when pregnancy is possible |
|---|---|
| Amoxicillin, other penicillins and cephalexin | These medicines are commonly used in Australia when clinically appropriate. The infection, allergy history, culture results, dose and treatment length still determine whether a prescription is suitable. |
| Nitrofurantoin | Nitrofurantoin is used for some lower UTIs. It is not suitable for every suspected kidney infection. The prescriber also considers kidney function, pregnancy timing and conditions that raise the risk of red-blood-cell breakdown, including G6PD deficiency. |
| Trimethoprim or co-trimoxazole | Trimethoprim affects folate metabolism. Use around conception or early pregnancy needs prompt review so the clinician can assess the infection, available alternatives and folic-acid advice for the individual situation. |
| Doxycycline and other tetracyclines | The TGA pregnancy database states that the tooth-discolouration concern for tetracyclines applies after 18 weeks of pregnancy. This does not mean doxycycline is automatically the preferred treatment earlier in pregnancy. The infection, available alternatives and pregnancy timing still require clinical review. Accidental early exposure does not by itself prove that harm occurred. Record the dose and dates and ask the prescriber or pharmacist. |
| Azithromycin and other macrolides | These medicines are used for selected respiratory and genital infections. Individual macrolides are not interchangeable, so the diagnosis, active ingredient, dose and pregnancy timing matter. |
| Ciprofloxacin and other quinolones | Another medicine may be preferred when pregnancy is possible and an effective alternative is available. A quinolone may still be selected for a resistant or difficult infection. Accidental exposure is not proof of pregnancy harm. |
| Metronidazole | Metronidazole is used for selected vaginal, dental and gastrointestinal infections. The route, dose, treatment length and reason for use should be checked rather than applying one rule to every metronidazole product. |
The Australian pregnancy database contains information for health professionals, but it is not designed for choosing or changing treatment yourself. A category letter does not replace an individual clinical assessment. Current Consumer Medicine Information and advice from the prescriber or pharmacist should guide the decision.
What If You Become Pregnant During the Course?
Do not panic or stop a prescribed antibiotic without advice. Accidental exposure does not automatically predict a pregnancy problem.
- Check the active ingredient, dose and treatment dates.
- Keep the packet and Consumer Medicine Information.
- Contact the prescriber or pharmacist promptly.
- Ask whether the course should continue, change or simply be documented.
- Arrange routine pregnancy care if the test is positive.
Research about antibiotics and miscarriage can be difficult to interpret because the infection, fever, inflammation and severity of illness may also affect pregnancy outcomes. It is inaccurate to claim that antibiotics as a group cause miscarriage. It is also inaccurate to promise that every antibiotic, dose and treatment stage is risk-free.
Do Antibiotics Affect Home Fertility Tests or Contraception?
Ovulation and pregnancy tests
The Fertility2Family midstream LH test has undergone manufacturer analytical-interference testing across three production lots. The study assessed negative samples, the 25 mIU/mL LH cut-off and 50 mIU/mL positive samples.
Ampicillin at 7.5 mg/dL did not produce a false-positive or false-negative result under the tested conditions. The same report found no interference at the evaluated concentrations from paracetamol, acetylsalicylic acid, ascorbic acid, atropine, gentisic acid, folic acid, caffeine, glucose, ethanol, urea or creatinine. It also reported no false-positive or false-negative results across urine pH 4 to 9 or specific gravity 1.000 to 1.035.
These findings apply only to the Fertility2Family midstream LH test and the substances, concentrations and conditions assessed. They do not prove that every antibiotic, medicine or fertility treatment is unable to affect every ovulation test. Follow the instructions supplied with the test and ask a pharmacist or prescriber about a medicine that was not assessed.
Pregnancy tests detect hCG rather than LH. Medicines containing hCG, including some fertility treatments, can affect pregnancy-test interpretation. The LH analytical report does not include interference testing for the separate Fertility2Family hCG device, so its findings cannot be applied to pregnancy tests. If an ovulation test becomes unexpectedly strong after ovulation or near a late period, read whether a
positive ovulation test can mean pregnancy
. Follow the pregnancy-test instructions, particularly the testing date, reading time and guidance about diluted urine.
If pregnancy tests remain negative and your period does not arrive, read the guide to a
late period with negative pregnancy tests
.
Hormonal contraception
Most antibiotics do not reduce the effectiveness of hormonal contraception. Rifampicin and rifabutin are important exceptions because they can reduce the effectiveness of some hormonal methods. Vomiting or severe diarrhoea can also affect oral contraceptive use. Ask the prescriber or pharmacist for method-specific advice if you are finishing contraception before trying to conceive.
When to Get Medical Help
Contact a GP or pharmacist if symptoms are not improving, you cannot keep the medicine down, treatment is prolonged, pregnancy is possible, fertility treatment is underway or either partner may have an STI.
Seek urgent care for:
- difficulty breathing, facial or tongue swelling, wheezing or collapse;
- severe abdominal or pelvic pain;
- heavy bleeding, dizziness or fainting when pregnancy is possible;
- high fever, back or side pain or persistent vomiting;
- severe, persistent or bloody diarrhoea.
Call triple zero on
000
for suspected anaphylaxis or another life-threatening emergency.
Frequently Asked Questions About Trying to Conceive While Taking Antibiotics
Can antibiotics make you ovulate early or delay ovulation?
A changed ovulation date while taking antibiotics does not prove that the medicine caused it. Illness, fever, sleep disruption, stress and normal cycle variation can shift timing. Seek GP advice if irregular or absent ovulation becomes a repeated pattern.
Does amoxicillin affect ovulation?
Amoxicillin is not a fertility medicine or contraceptive. A changed cycle while taking it does not prove that it altered ovulation. Illness and normal cycle variation may change the timing you expected.
What if I took doxycycline before knowing I was pregnant?
Record the dose and dates and contact the prescriber or pharmacist. An early accidental exposure does not by itself prove that harm occurred, but the reason for treatment and whether the course should continue still need individual review.
Can a UTI stop you from getting pregnant?
A straightforward lower UTI does not usually prevent conception, but pain or feeling unwell may make sex uncomfortable. Prompt treatment matters because a worsening infection or kidney infection needs medical review, particularly when pregnancy is possible.
Can antibiotics affect sperm?
Evidence differs between individual medicines, and fever or an infection involving the reproductive tract may also affect semen. A brief course does not create a universal three-month waiting period.
Can antibiotics cause a false pregnancy or ovulation-test result?
The Fertility2Family midstream LH report found no interference from ampicillin at the concentration tested. That result does not cover every antibiotic or the separate hCG device. hCG-containing fertility medicines, testing too early, reading outside the stated time and diluted urine can also affect interpretation.
Next Steps in Australia
If either partner needs antibiotics, keep the packet, note the active ingredient and treatment dates, and tell the prescriber where you are in the cycle. Treat the infection, follow any STI and partner-management instructions, and ask whether the exact prescription requires a temporary pause.
Ovulation tests can support LH tracking before expected ovulation, while pregnancy tests detect hCG once pregnancy testing is appropriate. The tests are not interchangeable, and neither can determine whether an antibiotic is suitable for you or confirm that ovulation occurred, implantation took place or a pregnancy is progressing normally. When you are ready to choose a format, you can compare Fertility2Family ovulation tests for repeated LH tracking or compare pregnancy tests for hCG testing when your testing date arrives.
Last reviewed: July 2026. Next scheduled review: July 2027.
References
Fertility2Family publishes Australia-focused fertility education. Articles are written by our editorial team and medically reviewed by Australian-registered health practitioners. We use Australian consumer medicine information, Australian clinical and public health guidance, and peer-reviewed research consistent with Australian care. We explain what the evidence suggests, what it cannot confirm and when to see a GP or fertility specialist.
Therapeutic Goods Administration: Prescribing medicines in pregnancy database. Australian pregnancy entries for the antibiotics discussed.
Therapeutic Goods Administration: Australian pregnancy categorisation system. Explains why category letters are not a simple safety ranking.
Therapeutic Goods Administration: Find information about a medicine. Australian Consumer Medicine Information and Product Information resources.
Healthdirect Australia: Antibiotics. Antibiotic use, treatment completion, side effects, resistance and allergic reactions.
Pregnancy, Birth and Baby: Medicines during pregnancy. Medicine review, pregnancy timing and advice not to stop prescribed treatment without speaking with a clinician.
Pregnancy, Birth and Baby: Ovulation and fertility. Fertile-window timing and the limits of cycle tracking.
Pregnancy, Birth and Baby: Pregnancy tests. hCG testing, timing, early negative results and repeat testing.
Healthdirect Australia: Urinary tract infection. Symptoms, urine testing, treatment and warning signs for kidney infection.
Healthdirect Australia: Chlamydia. Treatment, partner management, temporary abstinence and reproductive complications.
Healthdirect Australia: Pelvic inflammatory disease. Symptoms, treatment and risks to tubal fertility.
MotherToBaby: Paternal exposures. How paternal medicine exposure differs from medicine taken by the person who becomes pregnant.
Nantong Egens Biotechnology Co., Ltd.: Ovulation (LH) Test Analytical Performance Report, YS-IVDR-122-A02, version A/2, approved 30 March 2026. Manufacturer analytical performance report supplied to Fertility2Family. It assessed three production lots, three LH levels, ampicillin, selected substances, urine pH, specific gravity, FSH and TSH.
Crowe et al.: Antibiotics and fecundability among female pregnancy planners. Prospective cohort study of 9,524 pregnancy planners that found no appreciable overall association between recent antibiotic use and the chance of conception per cycle.
Mikkelsen et al.: Preconception use of antibiotics and fecundability. Prospective cohort study of 9,462 women trying to conceive. The authors could not separate the medicine from the infection being treated.
Bookstaver et al.: A Review of Antibiotic Use in Pregnancy. Peer-reviewed review of antibiotic groups used during pregnancy.
Muanda, Sheehy and Bérard: Use of antibiotics during pregnancy and risk of spontaneous abortion. Observational study illustrating why infection-related confounding must be considered.
NSW Health: Standard medications for tuberculosis. Rifampicin can reduce the effectiveness of the oral contraceptive pill.
RACGP: Emergency contraception, oral and intrauterine options. Rifampicin and rifabutin are liver-enzyme-inducing medicines that can reduce the effectiveness of some hormonal contraception.
Evidence limits: Antibiotics differ by active ingredient, dose, route and treatment length. Observational findings may be affected by the infection and severity of illness. Device-interference findings apply only to the Fertility2Family midstream LH test and the substances, concentrations and conditions assessed.