Sexually transmitted infections and reproductive outcomes

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Produced by The Fertility Society of Australia: Pre-Conception Health Special Interest Group and Your Fertility

Sexually transmitted infections (STIs) including chlamydia, gonorrhoea, genital herpes, human immunodeficiency virus (HIV), syphilis and the recently identified Mycoplasma genitalium are common in Australia. If they are left untreated they can adversely affect male and female fertility and other reproductive outcomes. Here is what you need to know about the possible health effects of STIs and how to avoid them.


Chlamydia is the most common STI in Australia. People who have chlamydia often have no symptoms and can therefore have the infection for some time without being diagnosed or treated.

In women, symptoms of chlamydia can include unusual vaginal discharge, a burning feeling when urinating, pain during sex, bleeding or spotting between periods or bleeding after sex, and lower abdominal pain. Untreated or repeated chlamydia infections can cause pelvic inflammatory disease (PID), which in turn can damage the fallopian tubes. Symptoms of PID include lower abdominal pain and tenderness, pain during sex, heavy and painful periods, and fever. Women with blocked or scarred fallopian tubes are at risk of infertility. If they do conceive, they are more likely to have an ectopic pregnancy, meaning that the pregnancy implants in the fallopian tube rather than in the uterus and cannot continue.

It is important to know that even if there are no visible signs of damage to the fallopian tubes, a past chlamydia infection can cause subtle damage to the lining of the fallopian tubes which reduces fertility. If you have open fallopian tubes but have trouble conceiving and consider infertility treatment you should be tested for past chlamydia infection to determine which type of infertility treatment is best for you.

In men symptoms of chlamydia can include discharge from the penis, discomfort when urinating and swollen and sore testicles. Chlamydia can affect sperm quality and function and cause inflammation in the urethra, prostate and epididymis (the part of the testicle where sperm is stored).

If you suspect that you have chlamydia see your GP as soon as possible and ask to be tested. With early detection and treatment with antibiotics, the effects of chlamydia can be avoided or reduced.


Gonorrhoea infection can cause similar adverse effects on fertility as chlamydia. While gonorrhoea overall is more likely than chlamydia to cause symptoms, women often have no symptoms. If symptoms are present, they can include unusual discharge from the vagina and pain when urinating.

In men, symptoms of untreated gonorrhoea may include painful urination, white or yellow pus-like discharge from the penis, and swelling and pain in the testicles.

As with chlamydia, if you suspect that you have gonorrhoea see your GP as soon as possible and ask to be tested. With early detection and treatment with antibiotics, the effects of gonorrhoea can be avoided or reduced.

Genital herpes

Genital herpes is caused by the herpes simplex virus (HSV). Symptoms include small, painful blisters on the genitals and a burning sensation when urinating. HSV cannot be cured and symptoms flare up from time-to-time, but there are drugs that can reduce the severity and frequency of these symptoms. Most women who have HSV in their body can expect at least one flare-up during pregnancy. Because HSV can be transmitted to the baby through direct contact with the virus during birth, it is recommended that pregnant women who have active blisters when they are close to
term have a cesarean section.


HIV is a virus which can be transmitted through sexual intercourse and to a baby during pregnancy and through breastfeeding. HIV cannot be cured and there is currently no vaccine to prevent it. With effective antiviral medications, people affected by HIV can live well and may wish to have children.

HIV can impair a woman’s fertility. For couples who want children where one partner is affected by HIV, the risk of transmission of the virus to the other partner and to the baby can be minimized by using various forms of assisted reproductive technology (ART) to conceive.


Syphilis is caused by bacteria which can be transmitted from mother to baby during pregnancy. So-called congenital syphilis can result in health problems for the child at birth and later in life. Syphilis can also cause miscarriage and stillbirth. Pregnancy-related complications due to syphilis are very rare in Australia because pregnant women are tested and if they are found to have the infection they can be safely treated with antibiotics, to prevent these complications.

Mycoplasma genitalium

Mycoplasma genitalium is a more recently identified but increasingly common bacterial STI. In women it can cause vaginal discharge, inflammation in the urethra and cervix, and PID, and can increase the risk of infertility. In some men the infection does not cause any symptoms but others can experience inflammation of the urethra, painful urination, and discharge from the penis. Mycoplasma genitalium can be effectively treated with antibiotics.

Main points to remember
• Safe sex practices, i.e. using condoms, is the best way to avoid STIs
• If you suspect that you have an STI, see your doctor as soon as possible
• Early detection and treatment of STIs significantly reduces the risk that they lead to infertility.