Getting pregnant with an IUD is exactly how things aren’t supposed to go. After all, if you decide to get an IUD, the entire point is to have an incredibly reliable form of contraception that allows you to control when—if ever—you get pregnant. But getting pregnant with an IUD can happen in some extremely rare occasions.
Track athlete Sarah Brown knows this firsthand. In July 2016, just four months after giving birth, Brown was training in hopes of making the U.S. Olympic track team for the 1,500 meter run. Brown didn’t plan to be pregnant while training for the Olympics, but her copper IUD failed…just as she was running her best race times ever.
“I went from crushing workouts to, all of a sudden, in the second interval of a workout, I thought I was running in sand. Racing wasn’t fun anymore,” Brown told New York magazine’s The Cut in 2016 when she was training. “It was really frustrating because we had concentrated so hard on doing things right, and I didn’t feel like I had overtrained. It was like, ‘Why is this happening? What’s wrong with me?’”
Brown eventually took an at-home pregnancy test that was negative, but a few weeks later, she went to see her doctor who determined that Brown was, in fact, pregnant. Brown’s IUD was removed, and her daughter was born in March 2016.
So, how likely is it that getting pregnant with an IUD will happen to you the way it happened to Brown?
First, let’s do a quick IUD refresher.
There are a few different kinds of IUDs, all of which are implanted inside the uterus to prevent pregnancy and last anywhere from three to 10 years.
Some contain progestin, a synthetic version of the hormone progesterone. It thickens cervical mucus, making it tougher for sperm to get to an egg. It also thins the uterine lining so that even if the sperm did reach an available egg, the fertilized egg would have a hard time implanting.
Hormonal IUDs include:
Then there's the copper IUD, Paragard, which is the kind Brown says she used. Those work by causing an inflammatory reaction that harms sperm, according to the Mayo Clinic, and they’re recommended for up to 10 years. That’s a full decade of pregnancy prevention when all goes according to plan—which it typically does.
Luckily, the available research shows that it’s extremely rare to get pregnant with an IUD.
“IUDs are a very, very reliable method of birth control,” Maureen Whelihan, M.D., an ob/gyn at the Center for Sexual Health & Education, tells SELF. Jason James, M.D., medical director at Miami's FemCare Ob-Gyn, agrees, but he also notes that even the best birth control can fail. “There’s nothing that’s 100 percent,” he tells SELF.
Here’s the generally accepted statistic: Fewer than one person out of every 100 with an IUD will get pregnant within the first year of use.
The Centers for Disease Control and Prevention (CDC) cites a 2011 Contraception review in its materials about effectiveness of different birth control methods. The review examined the largest and most methodologically sound data on the subject, concluding that the failure rate for Paragard and Mirena are 0.8 and 0.2 percent respectively. (Although progestin levels in hormonal IUDs can vary, it’s generally accepted that this number represents the failure rate for all hormonal IUDs. Also, since it’s pretty hard to mess up having an IUD the way you can mess up with, say, birth control pills, the failure rate for perfect and typical use with IUDs seem to be virtually the same.)
A 2017 study in Perspectives on Sexual and Reproductive Health studied 15,728 contraceptive use intervals (basically, periods of trying different forms of birth control) from 6,683 women over four years, also concluding that IUDs were only likely to fail 1 percent of the time in a period of 12 months.
As you can see, the overall point is that getting pregnant with an IUD is extremely rare.
Though it rarely ever occurs, people with IUDs can get pregnant for a few reasons.
The one that’s really in your control: Keeping your IUD past its removal deadline.
You may be more likely to get pregnant if you don’t remove your IUD per the manufacturer-approved timeline, Jessica Shepherd, M.D., a minimally-invasive gynecologist at Baylor University Medical Center at Dallas, tells SELF. How long is too long to keep your IUD past its deadline?
What’s interesting about this is that some research shows IUDs are actually effective past their manufacturer-approved expiration dates, but only in certain populations (which is why you definitely shouldn’t just decide to extend your IUD use on your own). For instance, a 2014 review in the journal Contraception found that Mirena was actually effective for up to seven years when it’s only recommended up to five, but these results were specifically in people who were at least 25 with children at the time of insertion. In that same demographic, Paragard was effective for up to 12 years (it’s recommended for up to 10). But, on the other hand, no evidence showed that Skyla was effective past its three-year deadline in any group of people.
Even these fascinating results about how long IUDs may be effective aren’t enough to say that you can go ahead and keep yours in for however long is convenient. Until the Food and Drug Administration (FDA) officially revises an IUD’s recommended usage, the way it did by bumping up Liletta’s maximum usage to five years instead of four in October 2018, you should take the current prescribing information seriously. Always ask your doctor about keeping your IUD past its recommended removal date. Otherwise, you could be rolling the pregnancy dice.
It’s also possible to get pregnant if an error during insertion means your IUD doesn’t stay in place.
For instance, if the IUD moves from the upper cavity of the uterus into the lower segment, it may not be as effective, Dr. Shepherd says.
Sometimes it’s even possible for the IUD to perforate the uterus, meaning it punctures the wall of the organ or goes all the way through it. However, according to the American College of Obstetricians and Gynecologists (ACOG), this only happens in about 1 out of 1,000 people with IUDs, based on all the available data (of which there admittedly isn’t a ton).
In any case, this is why doctors recommend that anyone who gets an IUD comes back a month later to make sure it's still nestled in the right place in the uterus. Dr. Whelihan says that many people “don’t show up for that visit because they feel fine and it’s an inconvenience, but it’s important."
This is also why doctors typically recommend that people who just got IUDs check their strings monthly for at least the first three post-insertion months. Being unable to feel the strings hanging from your cervix doesn’t automatically mean your IUD has migrated and left you vulnerable to pregnancy; the strings can curl up around the cervix or just generally be hard to feel. But if you can’t feel the strings and are experiencing any strange symptoms like pain, cramping, and bleeding—or if you have those symptoms even if you can feel the strings—you should see your ob/gyn to make sure everything checks out.
In rare instances, it’s also possible for your body to expel the IUD.
This basically means it can fall out, leaving you unprotected against pregnancy. But don’t get too nervous about this. Although there’s not a ton of science on the subject, the available data indicate that this doesn’t happen that often. According to the ACOG, expulsion happens in anywhere from 2 to 10 percent of all IUD users. This is most likely to take place soon after insertion, which is why that follow-up and checking your strings can be so important.
If someone does get pregnant while using an IUD, they're at a greater risk of issues like an ectopic pregnancy and miscarriage.
“Overall, IUDs prevent pregnancy very well,” Dr. James says. “But if [pregnancy while using an IUD] does occur, the risk of having an ectopic pregnancy is fairly significant.” An ectopic pregnancy is when the fertilized egg implants somewhere outside of the uterus, like in a fallopian tube. ACOG cites a 2004 American Journal of Obstetrics and Gynecology study on 17,360 IUD users, which found that 53 percent of pregnancies with IUDs wound up being ectopic.
Early symptoms of ectopic pregnancy include pelvic pain and light vaginal bleeding, according to the Mayo Clinic, but this can eventually progress into severe abdominal pain due to internal bleeding, extreme lightheadedness, and fainting. An ectopic pregnancy can be life-threatening if it’s not treated in time.
To be clear, since IUDs are so effective, when you use one you still have a lower risk of ectopic pregnancy than when you don’t, Dr. James explains. But the point is that, if you do conceive with an IUD, chances of it being ectopic are higher than if you conceived without one.
Getting pregnant with an IUD can also result in miscarriage, especially if the IUD is not removed. A 2012 review in Contraception examined nine studies about pregnancy outcomes in people who had IUDs, finding that people who got pregnant with an IUD and didn’t remove the device had a higher risk of issues such as pre-term delivery as well.
That’s why if you suspect or discover that you’re pregnant even though you have an IUD, you need to call your doctor right away.
Despite the slim chance of getting pregnant with an IUD, doctors stress that IUDs are generally an extremely safe and reliable way to control your reproductive future. “I love IUDs," Dr. Shepherd says. "They really are one of the best forms of birth control."
Additional Reporting by Zahra Barnes