Sexually transmitted infections, sometimes also called sexually transmitted diseases (STIs or STDs) are health conditions that are very uncomfortable to talk about. This is the reason why many of those affected choose not speak out and seek medical help. However, this is a very dangerous practice as many STIs can cause severe health complications if left untreated. Even when they are dormant – that is, when they don’t manifest any specific symptoms, it is still important to get proper treatment.

In this article, we will discuss the most common complications and their impact on general health in the long term.

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Risk of pelvic inflammatory disease (PID)

Pelvic inflammatory disease, or PID for short, is a relatively common condition that affects women. It occurs when bacteria from the vagina and cervix manage to find their way up to the upper genital tract. As such, it can be caused by various bacterial sexually transmitted infections such as chlamydia and gonorrhoea, but also bacterial vaginosis – a condition that is not transmitted through sex but instead occurs once when the vaginal flora gets disrupted in some way, leading to prevalence and over-reproduction of one type of bacteria that naturally exists within the vagina, but whose spread is limited by other microbes present.

PID can cause an array of uncomfortable symptoms:

  • Pain in the lower abdomen
  • Discomfort during sex and urination
  • Intensive menstrual periods
  • Presence of bleeding between periods
  • Unusual vaginal discharge
  • Fever
  • General malaise
  • Nausea and vomiting

According to numerous studies, around 10 to 15% of women affected by chlamydia will develop PID if they don’t seek timely treatment for their condition. Some scientists also speculate that untreated STIs that result in PID can also cause various fertility problems.

Infertility as a result of untreated STI

A very serious consequence of untreated STIs in both men and women can be infertility. With many of the common sexually transmitted diseases remaining asymptomatic for long periods of time, many couples can find out about the issues once they seek out help after failing to conceive a child.

Female infertility is, in most cases, caused by those STIs that have the ability to affect and permanently damage the fallopian tubes, while in men, the central risk factor is infection of the testicles (which is more often than not attributed to chlamydia infection). If it occurs, it leads to the reduction of the number of sperm cells being produced, making it more difficult to conceive.

According to numerous studies, the age group that is at the highest risk of contracting and STI are actually young people aged between 15 and 24 which comprise around 50% of all the new cases recorded annually. While in this age group fertility might not be high on the list of priorities, damaging the reproductive system and being diagnosed with infertility in young years can lead to significant relationship and mental health issues later in life.

Pregnancy complications: Miscarriage and ectopic pregnancy

Not every damage to the female reproductive system done by STIs will lead to infertility. Aside from problems when trying to conceive, untreated STIs can also cause a number of issues during pregnancy, with some of them being very serious and at times even life threatening, especially when it comes to the health of new-born baby.

Already mentioned pelvic inflammatory disease can cause significant scarring on the reproductive system, making it more difficult for fertilised eggs to reach the womb. As a consequence, eggs might get stuck in the fallopian tube, unable to move, causing an ectopic pregnancy – pregnancy that takes place outside of the womb. This condition can cause immediate health complications and even be fatal.

Study into the topic undertaken by the National Centre of Biotechnology Information (or NCBI for short) claims that more than 40% of all documented ectopic pregnancies can be attributed to various infection, including STIs.

In addition to this, certain bacterial STIs such as chlamydia can also cause foetus to die in the uterus or lead to miscarriage.

Epididymo-orchitis as a result of untreated STI

One especially painful complication that can occur in men if conditions such as chlamydia or gonorrhoea are left untreated is epididymo-orchitis, an inflammation and swelling of the part of the testicles that is tasked with producing sperm. The bacterial STIs are especially likely to cause this complication since they tend to infect urethra from where they can easily progress into the testicles if left untreated.

Can STDs increase the risk of contracting HIV?

Numerous studies have confirmed the hypothesis that inadequate STI treatment significantly increases the risk of getting affected by HIV if exposure occurs. In fact, study carried out by Palo Alto Medical Foundation (PAMF) seems to indicate that women affected by chlamydia are up to five times more likely to contract HIV is exposed as opposed to otherwise healthy individuals.1

With this in mind, we can say that proper and timely treatment of STIs is also an important part of prevention and reduction of HIV. This condition can cause severe damage to the body’s immune system, eventually compromising it entirely and leaving the body defenceless. As of now, there is no cure for HIV and this long term condition, if contracted, will have to be managed throughout the rest of person’s life.


One of the most dangerous STIs, syphilis progresses through three distinct stages. Ideally it should be treated early on, although treatment is possible even in the latest stage, although it would require hospitalization and most probably, the damage caused could not get reversed. While first two stages are more unpleasant than dangerous, the third stage is marked by severe health complications, sometimes even with a lethal outcome. Some of the documented syphilis complications include critical organ failure, stroke, paralysis, blindness, deafness, heart disease and dementia.

How can I prevent STI complications?

STI complications don’t occur often when the condition is properly managed and treated. So the best way to prevent further complications is to get tested regularly and start taking proper treatment as soon as possible. It is also helpful to keep in mind that many STIs can remain dormant for long periods of time, so just because you don’t notice any symptoms, you shouldn’t assume everything is in order if you had been engaged in unsafe sex. Testing is the only way to know for sure whether you contracted some of the common STIs.


  1. Chlamydia – Palo Alto Medical Foundation