STIs and Infertility: What Do I Need to Know?

Sexually transmitted infections (STIs) are passed between sexual partners. In many cases the infection causes uncomfortable or unpleasant symptoms. Men may notice swollen or sore testicles, or discharge from the penis, and women may experience unusual vaginal discharge, pelvic pain, or abnormal bleeding. However, some people will not experience any symptoms of pelvic infection, and therefore will not see a doctor to access the required treatment. Unfortunately, untreated infections can later impact the fertility of both men and women.

The World Health Organization (WHO) reports that there are over 30 types of bacteria, viruses or parasites that can be transmitted through sexual contact. Three infections that do not always cause symptoms, but may impact fertility, are chlamydia, human papilloma virus (HPV), and gonorrhea.

Human Papilloma Virus (HPV)

HPV is a virus that is known to cause cervical cancer in women, but has been poorly studied in men. However, recent research in China has shown that men who have difficulty conceiving are more likely to have HPV infection, than those who are fertile. Those with HPV infection were noted to have lower motility (movement) and reduced vitality of their sperm cells, which may make it harder to conceive naturally.


Chlamydia is a common STI caused by the bacterium Chlamydia trachomatis. It causes inflammation of the testes and epididymis (the area in which sperm cells mature and are stored). This inflammation can block the pathway needed for ejaculation to occur, and can also interrupt the healthy formation of sperm cells. Sperm may be less motile and may even be malformed, preventing conception from occurring.


Gonorrhea is caused by the bacterium Neisseria gonorrhea. Like chlamydia, gonorrhea can scar and block the sperm production duct, leading to infertility. The sperm produced may be less motile, incorrectly formed, and therefore less able to fertilize an egg for conception to occur.

Do I Need to Take Action?

If you have any concerns that you may have been exposed to an infection, it is important to visit a doctor to request STI testing. This is true regardless of whether the potential exposure occurred recently or in the distant past, and irrespective of whether you had or have symptoms.  If an STI is present, you will be able to access appropriate treatment.

If you are having difficulty conceiving with your partner and visit a fertility specialist for investigation, many clinics will run STI screening tests as standard. If you are unsure, check what your clinic offers.

If an STI is detected, appropriate treatment will be recommended to manage or eradicate the infection. An accurate STI diagnosis will also give your fertility team valuable information when analyzing your semen sample, especially if changes in the formation, development or movement of the sperm cells are noted. This may guide the fertility treatment they recommend for the best chance of successful conception.

Final Thoughts

STIs are common, but in some cases they do not cause any symptoms. This means that the infection may only be detected if it leads to reduced fertility or difficulty conceiving. If you are concerned about a past STI infection, the possibility of an infection without symptoms, or are having problems conceiving, it is important to speak to a doctor or request STI testing to rule out the presence of an infection.