Highlights from this article

  • Evidence on the association between IUDs and vaginal infections is a bit of a mixed bag. More research is needed in this area to resolve conflicting study results.
  • Some studies suggest that women with copper IUDs may have a higher prevalence of Candida (yeast), as well as higher rates of bacterial vaginosis (BV) and Trichomonas vaginalis infections. 
  • There is limited data on hormonal IUDs because they are newer and less popular worldwide. There is a possible association between hormonal IUDs and an increased chance for yeast infection over long periods of time. 
  • There is little evidence that hormonal IUDs increase risk for BV, though the risk seems to be highest in the three months post-insertion. We need more research to come to a clear conclusion. 
  • IUDs pose a minimal risk for PID. The small risk is highest in the first  few weeks post-insertion. 

If you’ve ever experienced the misfortune of forgetting to pick up your hormonal birth control pills from the pharmacy, you’ll likely appreciate why intrauterine devices (IUDs) are  beloved by many. First of all, they’re low-maintenance since they only require one appointment at the GYN every few years for insertion. Once they’re in, they’re basically mistake-proof, making them extremely effective (over 99%!) in preventing pregnancy. And if you change your mind about wanting to get pregnant (or just don’t want an IUD anymore) they’re also easily removable. 

But as most of us know all too well, in the world of vaginal health, there are sadly no free passes. Despite the IUD being a great option for birth control, you may have heard that IUDs can cause other problems, like increasing your risk for vaginal infections (UTIs, BV, yeast infections, etc.)  But do they? And if so, do the risks outweigh the benefits compared to other birth control methods?

Below, we cover existing research on the relationship between vaginal infections and IUDs, so you have all of the info you need to make the best birth control decision for you! 

What is an IUD? 

An IUD is a form of long-acting reversible contraception (LARC). To insert, a medical professional dilates your cervix and places the IUD in your uterus. 

In addition to preventing pregnancy, IUDs are also prescribed by doctors as a treatment for very heavy bleeding during your period, painful periods (dysmenorrhea), pelvic pain/endometriosis, and endometrial hyperplasia/endometrial cancer. 

Currently, there are 5 available IUDs on the market in the U.S. Of women in the U.S. who use IUDs, three quarters use a hormonal one, and about one quarter use copper.  (Another use for the copper IUD is as emergency contraception for up to 5 days after unprotected sex.)

Here are some quick stats on the five types (for your convenience and edification):

*Paragard has FDA approval for 10 years, but recent data shows it is effective for up to 12 years. Follow your GYN’s recommendation for the best removal/replacement timeline!

Let’s break down the research for each IUD type (copper and hormonal) and their effects on the vagina.

Do non-hormonal (copper) IUDs cause vaginal infections or create imbalances within the vaginal microbiome?

Here’s the short (and frustrating) answer: it’s possible that copper IUDs influence microbes in the vagina, but we need more data since the evidence is mixed. 

Ok, but what does that mean for my vagina? Basically, some women with copper IUDs may have a higher prevalence of Candida (yeast), as well as higher rates of bacterial vaginosis (BV). Here’s the research to back that up:  

One study published in 2014 examined 108 women who received a copper IUD and found that after 12 months, they had a slightly higher prevalence of Candida species, mycoplasma, and signs of inflammation than they did prior to getting their IUD. Another study that assessed a copper IUD used by 95 women in Iran found that there was a higher prevalence of Candida in vaginal samples 3 months after insertion. But, since these studies had a limited number of participants, more research is needed to say for sure if copper IUDs are associated with an increased risk of yeast infection. 

Researchers have also studied whether copper IUDs shift the makeup of the vaginal microbiome, as some vaginal infections are not caused by a single microbe (we’re looking at you, bacterial vaginosis). 

One 2018 study of women in Thailand found no difference in the rate of bacterial vaginosis (BV) between women with and without a copper IUD. However, a study published in 2020 showed that BV occurred more frequently in participants with copper IUDs than in participants with a hormonal IUD or not using contraception. Additionally, another 2021 study conducted in Africa found that women with copper IUDs had a slightly higher risk of BV compared to women without IUDs. 

Do non-hormonal (copper) IUDs increase your risk for STI transmission?

Another question that often comes up is whether copper IUDs increase your risk for STI transmission. 

Before we go into that relationship, remember that the pathogens that cause STIs are sexually transmitted and do not come from the IUD itself. 

That said, in a 2019 study that compared the rates of sexually transmitted infections (STIs) accross women using different methods of contraception, women with copper IUDs had an increased rate of Trichomonas vaginalis infections, but not other types of STIs such as Chlamydia and N. gonorrhoeae (gonorrhea).

Researchers believe that susceptibility to a Trichomonas infection might be influenced by the microbiome. Meaning, since there’s some evidence to suggest that copper IUDs are related to a higher prevalence of BV, this disruption to the microbiome might also pave the way for Trichomonas infections, as bacterial vaginosis can increase your risk for STIs. But more research is needed to confirm if changes to the microbiome are a result of the Trichomonas infection or part of their cause (basically a “chicken or the egg” question). 

Do hormonal IUDs cause vaginal infections?

There is even less data on hormonal IUDs and their impact on the vaginal microbes compared to copper IUDs. Why? Hormonal IUDs are newer, and mainly available in the U.S. and Europe. Copper IUDs have been around longer, and are used more widely around the world, so there are more opportunities for researchers to collect data on them.

Do hormonal IUDs cause yeast infections? 

TL;DR: it looks like that over a longer period of time (say, several years), there could be an association between hormonal IUDs and an increased chance for yeast infection. However, it’s unclear why–––so back to the lab!  

There isn’t a clear verdict on whether or not hormonal IUDs are associated with yeast infections. On the one hand, this report of three different types of studies all conclude that hormonal IUDs are not associated with an increased risk of yeast infections. Also, the same 2014 study that looked at copper IUDs also took a look at 42 women with hormonal IUDs, again looking for Candida species, Mycoplasma, and signs of inflammation. Unlike copper IUDs, the cohort of women receiving a hormonal IUD did not have an increase in any of the three markers of infection one year after insertion.

That said, another study of women who received their IUDs in 1998 looked across a 7 year period after IUD insertion, and saw that the chance of having yeast present in a vaginal sample is increased during years 4-7 compared to the first year. 

A more recent (2018) study looking at the microbes present over five years after hormonal IUD insertion and also found an increase in Candida over time compared to before insertion. Additionally, one recent study from 2020 did find that participants with a hormonal IUD did have an increased chance of having a yeast infection 2 years after their IUD was placed, compared to copper IUD and a control group without contraception. 

Do hormonal IUDs cause bacterial vaginosis or other microbial disruptions? 

As far as hormonal IUDs’ associations with other shake-ups to the microbiome: one 2014 study looked at vaginal microbiomes 1 week before and 12 weeks after hormonal IUD placement and found that the vaginal microbiome changed very little for the 11 participants in the study. However, a more recent study with 252 women who all received Mirena looked at a longer time course for changes in the vaginal microbiome and saw a temporary decrease in Lactobacillus and an increased chance of BV for participants at 3 months post-insertion. But, that trend was reversed at both 1 and 5 years post-insertion, meaning the microbiome was able to return to its pre-insertion state. 

IUDs and Pelvic Inflammatory Disease 

If you’ve Googled “IUD” and “infection” (which is very likely if you’ve landed here, and we’re so glad you did!) you may have come across Pelvic Inflammatory Disease (PID). PID refers to an infection in your upper gential tract, such as in the uterus or fallopian tubes. While it’s possible for an infection causing PID to have started out in the vagina, PID is considered a separate condition from a vaginal infection. 

If your IUD is being placed by a trained medical professional (which it should be!), the chance of vaginal microbes moving into the uterus during the insertion process is very low. One 2012 study of over 57,000 IUD insertions in northern California found that the overall risk for PID after IUD insertion was 0.54%. If you are considering getting an IUD and are worried about your chances of PID, definitely talk to your OB-GYN about your options and whether or not you could have any risk factors for PID.

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I’m thinking about getting an IUD but I’m worried about vaginal infections 

Though having an IUD usually means you can adopt a “set it and forget it” attitude about birth control, getting one can feel like a big decision for many people, especially those who experience recurrent vaginal infections. 

We know that all of this mixed evidence on IUDs and their relationship to yeast can be frustrating. We need more studies on the effects of IUDs on the vaginal microbiome, especially given their increasing popularity. IUD usage in the U.S. has been on the rise since the 1990s. Copper IUDs are also used widely across the globe. More types of copper IUDs,  in addition to Paragard, are also expected to be approved in the U.S. soon. 

While researchers keep working on these important questions, here are a few things you can do if you’re thinking about getting an IUD and have had your fair share of pesky vaginal infections!: 

  • Talk to your doctor about your overall risk factors, and discuss what preventative measures you can take before getting your IUD inserted
  • Take an Evvy test before getting your IUD inserted. This can help you to track any changes after insertion because you can test overtime with Evvy (and in case you were wondering,  yes, you can swab your vaginal microbiome with an IUD inserted!)
  • Consider the pros and cons of different types of IUDs for your body
  • If an IUD isn’t the right choice for you, consider other long-acting reversible contraceptive methods, such as Nexplanon, the birth control implant that goes in your arm

FWIW, you deserve a reliable birth control method that doesn’t mess with your vaginal microbiome or cause you undue anxiety! Team Evvy is here to support your journey in finding a birth control method that works for you so you can feel in control of your body and reproductive health!