STI-related infertility is less common in men than in women. This is partly because STI infections in men are more likely to cause symptoms. They are therefore more likely to be treated. 

This article discusses STI-related infertility. It also looks at individual STIs and how each one might cause infertility.

STIs can cause infertility in both females and males. In females, an untreated STI can cause inflammation and scarring in the fallopian tubes and other reproductive organs. This makes it hard for sperm to reach an egg.

Scarring in the fallopian tubes can also lead to ectopic pregnancy. An ectopic pregnancy occurs when a fertilized egg implants outside of the uterus. An unrecognized ectopic pregnancy can be life-threatening.

In males, the epididymis and urethra can be damaged by an untreated STI, leading to fertility problems. The epididymis is the long tube that transports sperm from the testes. The urethra is the tube that transports urine and semen out of the body.

Chlamydia

Chlamydia infects more than 1.7 million Americans every year. Extensive data shows that untreated chlamydia can lead to infertility in females.

Up to 70% of females with chlamydia don’t have any symptoms. Left untreated, even chlamydia that doesn’t have symptoms can eventually lead to pelvic inflammatory disease (PID). PID is one of the leading causes of preventable infertility.

PID causes a large amount of inflammation or swelling in the fallopian tubes. These are the tubes that transport eggs to the uterus. As PID progresses, scar tissue can form inside and outside the fallopian tubes. This scar tissue can block the tubes so a fertilized egg can not travel to the uterus. This is known as tubal infertility because the problems originate in the fallopian tubes.

Research suggests that chlamydia infections are responsible for close to half of all cases of tubal infertility in the developed world. There is conflicting evidence about what role chlamydia plays in male infertility.

Gonorrhea

Gonorrhea can lead to infertility in the same way as chlamydia. Like chlamydia, gonorrhea can go undetected for long periods of time. Most females with gonorrhea do not have symptoms.

Gonorrhea often causes tubal damage. Somewhere between 10% and 20% of females with untreated gonorrhea will develop PID. Gonorrhea infections probably account for between 10% and 20% of PID cases overall.

Gonorrhea can also cause problems with sperm health in many men. Together, gonorrhea and chlamydia are the major causes of preventable infertility both in the U.S. and around the world.

Mycoplasma

Females with PID who have neither gonorrhea nor chlamydia may have mycoplasma. Infection with this sexually transmitted bacterium may be more common than gonorrhea.

Mycoplasma infections have also been associated with PID and infertility in females, though not as often as chlamydia or gonorrhea. There is also some evidence suggesting that mycoplasma may lead to reduced fertility in males. 

Herpes

There is limited evidence to suggest that herpes may be associated with infertility in males. However, to date, there has been very little research on the topic. What research there is suggests that herpes infection may be associated with reduced sperm count.

Finally, herpes viruses have been found inside sperm cells. It is uncertain what implications this may have for establishing a successful pregnancy. 

HIV

HIV can cause biological changes that may affect how reproductive organs function. This can result in infertility. Several HIV/AIDS-related comorbidities are also associated with infertility. These include:

OrchitisAcute epididymitisPID

There is also some suggestion that, like herpes, HIV can affect sperm health.

HIV can also complicate the process of having children or undergoing fertility treatment. This is because HIV is sexually transmitted, and healthcare providers want to be sure it isn’t passed from one partner to another.

Fortunately, there are assisted reproduction options that can make having children when HIV positive much safer.

Summary

Untreated STIs can cause infertility. One of the most common ways this happens in females is when undetected chlamydia or gonorrhea infection progresses to pelvic inflammatory disease (PID). PID can cause scarring, which prevents a fertilized egg from reaching the uterus. It can also lead to ectopic pregnancy, which is a medical emergency.

Some STIs may also cause fertility problems in males. The best way to prevent STI-related infertility is to make sure you are regularly screened for STIs.

A Word From Verywell

Most people who have these STIs will not become infertile. This is why it’s so important to be regularly screened for STIs if you are in a higher-risk group. People who receive timely treatment are much less likely to develop fertility problems as a result of their infection.

Regular STI screening helps find infections that may not have symptoms. Screening and treatment aren’t just important in slowing the spread of STIs. They can also help preserve your ability to have children.