You had sex with a new partner a few months ago and now have some unusual discharge and pelvic pain that doesn’t seem to be going away. You got tested for a yeast infection and that wasn’t it and you aren’t on your period. So, what’s going on? 

It’s possible that you caught an STI from this partner which has developed into pelvic inflammatory disease (PID). PID happens when certain disease-causing bacteria migrate from the lower to the upper genital tract. Most of the time, this is due to an untreated STI. It affects around 4.4% of cisgender women in their reproductive years who are sexually active.

Fig 1 → The upper and lower female genital tract

If PID is untreated, it can cause damage to the endometrium, fallopian tubes, and ovaries  as well as lead to other conditions such as chronic pelvic pain, infertility, and ectopic pregnancy (when the embryo implants outside of the womb). PID can also cause severe illness such as sepsis, requiring hospitalization.

We know this sounds scary and serious — it’s important to remember that not everyone who has an STI will get PID, but the former does increase the risk of the latter, so it’s best to understand the risks and get tested regularly!

What’s the link between pelvic inflammatory disease and STIs? 

Pelvic inflammatory disease can develop when the internal surface of the womb (called the endometrium) is damaged, allowing pathogens to ascend into the upper genital tract via the cervix. This damage can be caused by STIs like chlamydia and gonorrhea. A relationship between bacterial vaginosis (BV) and PID has also been shown, but more research is needed.

It’s still unclear why some people with STIs get PID and some don’t, but there are some factors that are associated with a higher risk. This includes being at a younger age when you first had sex, having had a greater amount of sexual partners, having female partners, and having a history of STIs. 

STIs are treatable and preventable, so it’s important to get tested regularly — in addition to practicing safe sex — to help prevent any infection from progressing into PID. This is true even if you feel fine! Many people with STIs have no symptoms at all. You can get STI testing at your OB-GYN or for free at your nearest women’s health clinic such as Planned Parenthood

What types of STIs put me at higher risk for PID? 


You probably remember the iconic quote in Mean Girls: “You're going to want to take off your clothes, and touch each other. But if you do touch each other, you *will* get chlamydia... and die.” 

By now, you probably know that if you practice safe sex, you can do all the clothes taking-off and touching each-other you want without getting chlamydia (and dying). 

However, chlamydia does increase risk of PID. Chlamydia is caused by the bacteria Chlamydia trachomatis and affects around 4% of cis women of reproductive age. It is important to note that research shows around 70% of people with chlamydia won’t have any symptoms

If chlamydia isn’t treated, C.trachomatis can travel from the cervix into the upper reproductive tract and cause PID

However, having chlamydia is not a guarantee for developing PID. It’s estimated that about 14% of people with chlamydia will go on to develop PID.  Some research suggests that people with asymptomatic chlamydia are less likely to develop PID, Nevertheless, given the potential consequences of PID, STI testing is highly recommended. 


Gonorrhea is caused by the bacteria Neisseria gonorrhoeae and shares the title with chlamydia as the top causes of PID. Not so fun fact, these two conditions are also the most commonly reported bacterial STIs in the U.S. 

Again, having gonorrhea does not mean that you will definitely develop PID. But people with gonorrhea are more than four times more likely than those without it to develop PID. You should also be aware that, according to some studies, PID that follows gonorrhea can bring on more severe symptoms

Around half of those who have gonorrhea won’t have any symptoms at all, which can make it tricky to know whether you have the infection (and the higher risk of PID that comes with it). The best defense we currently have is practicing safe sex, receiving regular STI screenings, and treating any infections that are acquired as soon as possible.


It may be less well-known than its peers, but trichomoniasis, commonly referred to as “trich” is actually the most common, curable STI. It’s caused by a parasite called Trichomonas vaginalis, which can be passed from one person to another during sex and bring on infection by entering into the lower genital tract. 

When it’s left untreated, it can enter into the upper urinary tract and—you guessed it—play  a role in Pelvic Inflammatory Disease. While there is a clear association between trichomoniasis and PID, there is limited evidence for fully understanding the connection between the two. 

According to one study, T. vaginalis was present in around 13% of folks with PID. Plus, people with trichomoniasis were twice as likely to have endometritis, a condition where the lining of the womb gets inflamed and irritated, which is linked to PID. 

We probably sound like a broken record at this point, but only about 30% of people with trichomoniasis will have any symptoms, so it really is important that you get screened for STIs regularly. 

Mycoplasma genitalium

First discovered in the 1980s, Mycoplasma genitalium is a type of bacteria that we’re still learning about, but has been recognized as an emerging sexually transmitted pathogen. It is associated with a range of diseases, including cervicitis, infertility, and PID. 

One study of 682 cisgender women found that 31% of those who tested postive for M. genitalium went on to develop PID, while the CDC estimates that those who do test positive are twice as likely to get PID then those who don’t.  However, we still don’t know a lot about M. genitaliumthe CDC adds that there isn’t enough data to show that treating M.genitalium can prevent PID.

Herpes simplex virus (HSV-2) 

Famed for causing annoying cold sores around the mouth, herpes simplex virus (HSV) is another STI that may be involved in the development of PID, though there is not enough evidence to support this hypothesis at this time.

There are eight different types of herpes, but HSV-2 is the one to watch when it comes to PID (HSV-1 is to blame for the cold sores!).

One study found that people with HSV-2 were more likely to have endometritis, but did not show that HSV-2 definitely went on to cause PID. However, because endometritis and PID are closely linked, this supports the theory that HSV-2 could also be associated with it. 

As with so many of the other topics we cover, far more research is needed here—the study mentioned above was done in 2006, in response to another done in 1985! 

How do I know if I have pelvic inflammatory disease? 

It’s not always straightforward to figure out whether you have PID. For one, many people who have it don’t have any symptoms at all—meaning that you have to get tested to know if you do. If you do have symptoms, they could be anything from mild to severe, and can be general in nature. Some common symptoms include lower abdominal pain, pelvic pain, increased vaginal discharge, irregular bleeding, fever, pain during sex, and pain while peeing. 

Unfortunately, diagnosing PID is quite difficult as there is not a “gold standard” diagnostic criteria. Diagnosing PID includes a pelvic exam to look for signs of infection, and testing for any of the pathogens mentioned above. On the plus side, Pelvic Inflammatory Disease is entirely preventable with early detection and treatment of STIs and diagnosing and treating STIs is a very simple and well-defined process.

When it comes to your body, we believe that the best defense is a good offense, and Evvy’s Vaginal Health Test can help you better understand which types of bacteria are present within your vaginal environment — though we don’t currently test for STIs. While only a doctor can diagnose you, Evvy’s test can give you some useful clues as to what might be going on down there and pick up on any potentially harmful bacteria before PID fully develops. Our test is an addition to STI screening, not a substitute, so be sure to get tested regularly for STIs — including bloodwork!

Recurrent symptoms? Meet Evvy's at-home vaginal microbiome test, approved by leading OB-GYNs.
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