Let’s talk about what really happens when IUDs fail.
You might’ve seen that viral Facebook post — or meme — with a photo of a newborn baby holding the mom’s IUD. The post has since been deleted, but it raised a lot of questions about how likely it is to get pregnant with an IUD and what you should do if it happens to you.
In the original Facebook post, the mother shared the photo with the caption “Mirena fail!” followed by her baby’s weight and height, and a note that the “IUD was found behind the placenta.” Given the last detail, the photo was most likely staged and the baby did not come out actually holding the mom’s IUD.
However, the photo has already been shared thousands of times on Twitter, Instagram, and Reddit without the original source or any context — which has undoubtedly led to some confusion among people about the IUD and pregnancy.
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Yes, it can happen. It’s very rare, but the failure rate of a hormonal IUD is about 0.2%.
Unfortunately, no birth control method is 100% effective. “We know the IUD is incredibly effective but there are still failures — we even see failures with tubal ligations, and that’s just because there’s no completely perfect method out there,” Gunter told BuzzFeed Health.
There are several kinds of hormonal IUDs, the most common ones in the US being Mirena and Skyla (a slightly smaller version). Mirena is 99.8% effective for up to five years with a failure rate of 0.2%, and Skyla is 99.6% effective for up to three years with a failure rate of 0.4%. Both options are inserted into the uterus and release a type of progestin hormone called levonorgestrel to prevent pregnancy. There’s also the copper IUD, which is 99.2-99.4% effective, so the failure rate is about 0.6-0.8%.
The failure rates for IUDs are very, very small but they still exist — meaning some people just get unlucky. A 2011 literature review from the American Congress of Obstetricians and Gynecologists (ACOG) found 36 reported cases.
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“We don’t know exactly why the IUD fails and some women still get pregnant,” Gunter said, mainly because it hasn’t been well studied.
“It could be that it shifted or moved somewhere in her uterus where it stopped working, or since the IUD works by changing the cervical mucus, maybe her partner’s sperm had some incredible strength and mucus-penetrating ability, who knows,” Gunter said.
Just to clarify, we’re talking about the IUD failing to prevent pregnancy while it is still successfully implanted in the uterus. This is not the same as an IUD failing to implant or “IUD expulsion,” which can occur in 2-10% of women in the first year after insertion. This is why doctors recommend checking the IUD threads once a month to make sure it’s in place.
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If you do get pregnant with a hormonal IUD, there’s a higher risk of ectopic pregnancy, infection, miscarriage, and premature delivery.
The first risk, an ectopic pregnancy, means that the fertilized egg grows outside the uterus and the pregnancy occurs in the fallopian tubes instead. This is an emergency that requires immediate medical attention — if left untreated, ectopic pregnancy can cause internal bleeding, infertility, and even death.
If the fertilized egg successfully implants in the uterus and you continue the pregnancy with a hormonal IUD, there are different risks. These include infection or sepsis, says Gunter, and also miscarriage, premature delivery, or very rarely, death. However, just because these can happen doesn’t mean they will happen.
“We do know there’s a slightly higher risk of a negative outcome with the pregnancy if you still have a hormonal IUD, but we don’t know how high or have any percentages because there just haven’t been many studies on this yet,” Gunter said. So if you have an IUD and think you’re pregnant, don’t panic — just go see your doctor as soon as possible.
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