Getting pregnant with an IUD is rare, but it does happen, and the usual clue that something is off, a missed period, can be unreliable when your IUD has already changed your cycle. Hormonal IUDs cause lighter periods or no periods at all in many users, which makes it harder to spot the earliest sign of pregnancy. Knowing what else to look for, and when to take a test, can help you catch a pregnancy early if one occurs.
How Rare Is Pregnancy With an IUD?
IUDs are among the most effective forms of birth control available. Hormonal IUDs have a cumulative failure rate as low as 0.31 per 100 women within the first five years. Copper IUDs, which can stay in place for 10 to 12 years, have a cumulative failure rate of roughly 2.1% to 2.8% over that full duration. In any single year of use, fewer than 1 in 100 people will become pregnant with either type.
That said, “rare” is not “impossible.” IUDs can fail if they shift out of position. Younger people who haven’t been pregnant before may face a slightly higher chance of the device moving because the uterine cavity is smaller and placement can be trickier. The IUD can also partially slip out (called expulsion) without you realizing it, especially in the first few months after insertion.
Why a Missed Period Isn’t Always the Clue
With a copper IUD, your cycle typically stays regular, so a late or missing period is a meaningful signal. But hormonal IUDs (like Mirena, Kyleena, Liletta, or Skyla) thin the uterine lining and often reduce bleeding dramatically. Some people stop getting periods entirely. That’s normal and expected, but it removes the one symptom most people rely on to detect pregnancy early.
Hormonal IUDs can also cause spotting between periods, irregular cycles, and cramping, all of which overlap with early pregnancy symptoms. This overlap is the core challenge: your body’s signals while using a hormonal IUD can look a lot like early pregnancy, and vice versa.
Symptoms to Watch For
The physical signs of pregnancy with an IUD are the same as any early pregnancy. What changes is how much attention you need to pay to them, since you can’t always count on a missed period as your first alert. Watch for:
- Breast tenderness or swelling that feels different from your usual premenstrual changes
- Nausea, especially in the morning or triggered by certain smells
- Unusual fatigue that doesn’t match your sleep or activity level
- Frequent urination without an obvious cause like increased fluid intake
- A period that suddenly stops or changes when your pattern on the IUD had been predictable
No single symptom is definitive. Many of these overlap with PMS, stress, or normal hormonal fluctuations. The key is a cluster of symptoms appearing together, or a noticeable change from your personal baseline. If your body feels different from its usual pattern on the IUD, that’s worth investigating.
When and How to Take a Pregnancy Test
A standard home pregnancy test works the same way whether or not you have an IUD. The device doesn’t interfere with the test’s accuracy. If you suspect pregnancy, take a test with your first urine of the morning, when the pregnancy hormone is most concentrated. Most tests are reliable from the first day of a missed period, or about two weeks after conception.
If your hormonal IUD has already stopped your periods, you won’t have a “missed period” to trigger testing. In that case, test whenever you notice symptoms that feel unusual for you. Some people with hormonal IUDs choose to take a test once a month for peace of mind, and that’s a reasonable approach if the uncertainty bothers you.
If a test comes back positive, contact your healthcare provider right away. Early confirmation matters more with an IUD pregnancy than a typical pregnancy because of the higher risk of complications.
Why Ectopic Pregnancy Is a Concern
When pregnancy does occur with an IUD in place, the chance that it’s ectopic (the embryo implants outside the uterus, usually in a fallopian tube) is higher than with pregnancies that happen without contraception. An ectopic pregnancy cannot develop normally and can become a medical emergency if the tube ruptures.
Early signs of ectopic pregnancy are often subtle. You might notice light vaginal bleeding and pain in your pelvic area. Some people feel pain in one shoulder, which happens when internal bleeding irritates the diaphragm. As it progresses, symptoms can escalate to dizziness, feeling faint, rapid breathing, or clammy skin. These are signs of internal bleeding and require emergency medical care.
Not every IUD pregnancy is ectopic. But the risk is elevated enough that any positive pregnancy test with an IUD calls for prompt evaluation, including an ultrasound to confirm where the pregnancy is located.
What Happens if You’re Pregnant With an IUD
If pregnancy is confirmed, the next step is usually an ultrasound to check both the location of the pregnancy and the position of the IUD. Your provider will discuss your options, and if you choose to continue the pregnancy, the IUD’s removal becomes an important decision.
Leaving an IUD in place during pregnancy significantly raises the risk of complications. A 2012 systematic review found that pregnancies with a retained IUD had spontaneous miscarriage rates between 48% and 77%, and preterm delivery rates between 7% and 25%. Other risks included infection and premature rupture of membranes.
Removing the IUD early in pregnancy substantially improves those numbers. The best available evidence showed that miscarriage rates dropped from 54% to about 20% after early removal, and preterm delivery rates fell from 17–18% to 4–14%. The outcomes don’t return completely to baseline, but they improve considerably. Removal is generally recommended when the IUD strings are visible and accessible, making the procedure straightforward.
How to Check That Your IUD Is in Place
One practical way to catch a problem early is to periodically check that your IUD hasn’t moved. Most IUDs have thin strings that hang through the cervix into the upper vagina. You can feel for them by inserting a clean finger and reaching toward your cervix. You should feel the strings but not the hard plastic of the device itself.
If you can’t feel the strings at all, or if you can feel the rigid bottom of the IUD poking through the cervix, the device may have shifted. This doesn’t necessarily mean you’re pregnant, but it means the IUD might not be protecting you effectively. Use a backup method of contraception and schedule an appointment. Your provider can use ultrasound to confirm whether the IUD is still properly positioned in the uterus.
Checking your strings once a month, such as after your period ends, is a simple habit that takes seconds and can alert you to displacement before it leads to an unintended pregnancy.