Why Does My IUD Hurt? Causes & When to See a Doctor

IUD pain has several possible causes, and the timing and character of that pain usually point to different explanations. A sharp cramp during insertion is a normal response to the cervix being opened and a device being placed inside the uterus. Lingering discomfort over the following weeks often reflects the uterus adjusting to a foreign object, with local inflammation playing a central role. But pain that shows up later, worsens suddenly, or doesn’t follow a clear pattern of improvement can signal a complication that needs medical attention.

What Makes Insertion Hurt

The insertion procedure involves grasping the cervix with a small clamp called a tenaculum, then passing the IUD through the cervical canal into the uterine cavity. Both steps can be painful because the cervix has a dense network of nerve endings, and the uterus responds to being stretched with cramping contractions. In clinical studies measuring pain during insertion, women report a wide range of experiences: median pain scores during tenaculum placement alone have been recorded around 30 to 44 on a 100-point scale, meaning the typical experience sits somewhere between moderate and fairly uncomfortable.¹ Those numbers reflect averages, though. Some people barely flinch; others find it intensely painful.

One factor that consistently shows up in the research is anxiety. Pre-procedure anxiety has been significantly associated with higher pain during tenaculum placement.¹ This doesn’t mean the pain is “in your head.” Anxiety genuinely amplifies the brain’s processing of pain signals. Knowing what to expect, breathing techniques, and having a provider who communicates step by step can meaningfully change how the procedure feels.

Why Cramping Continues After Insertion

Once the IUD is in place, your uterus treats it the way it treats most foreign objects: with an inflammatory response. With copper IUDs in particular, the device triggers a local increase in prostaglandins, the same chemicals that drive menstrual cramps. Research has shown that prostaglandin levels in the uterine lining rise in women wearing IUDs, and because prostaglandins increase blood flow and vascular permeability, they contribute to both cramping and heavier bleeding.² This is why ibuprofen, a prostaglandin-blocking drug, is often the first thing recommended for post-insertion cramps.

For most people, this cramping is worst in the first few weeks and gradually settles. A study tracking copper IUD users over time found that about 38% reported more menstrual pain than usual in the first nine weeks, and roughly two-thirds reported heavier bleeding during that same window. Over the following months, both complaints decreased, with the percentage reporting heavier bleeding dropping to about 48% in later periods.³ The trajectory matters: things getting gradually better is a normal adjustment, while things getting suddenly worse is not.

How Copper and Hormonal IUDs Differ

Copper IUDs and hormonal (levonorgestrel-releasing) IUDs cause pain through somewhat different mechanisms, and understanding which type you have helps you know what to expect.

The copper IUD works by creating a hostile environment for sperm using copper ions. It doesn’t suppress ovulation or thin the uterine lining, so your natural menstrual cycle continues largely unchanged, except that the inflammatory response to the copper tends to make periods heavier and crampier, especially in the first several months. That roughly-one-third of users still reporting more menstrual pain months later isn’t trivial, though the trend is toward improvement.³

Hormonal IUDs release levonorgestrel directly into the uterus, which causes a very different set of tissue changes. The hormone triggers extensive transformation of the uterine lining, thinning the surface layer and altering blood vessel structure, specifically suppressing the formation of spiral arteries and promoting larger, dilated vessels instead.⁴ The practical result is typically lighter periods and less cramping over time, which is why hormonal IUDs are sometimes prescribed specifically for heavy or painful periods. However, in the first few months, irregular spotting and occasional cramping are common as the lining undergoes these changes. The adjustment period for a hormonal IUD is real, even if the long-term outcome is usually less painful than a copper one.

When the Device Doesn’t Fit the Uterus

Here is something that surprises many people: standard T-shaped IUDs are often larger than the uterine cavities they’re placed in, particularly for women who have never been pregnant. Research measuring uterine dimensions has found that the discrepancy between IUD size and cavity size can be considerable.⁵ When the horizontal arms of the IUD are wider than the cavity, they can press into the muscular wall of the uterus, causing persistent cramping, embedding, or even contributing to expulsion.

This mismatch is a significant and underappreciated source of ongoing IUD pain. If you experience chronic, dull pelvic aching that doesn’t follow the expected pattern of gradual improvement, the device may simply be too large for your anatomy. Smaller-frame IUDs exist for this reason, and some providers now use ultrasound measurements before insertion to select the right size. If your pain hasn’t improved after the first three to six months and your provider hasn’t discussed uterine sizing, it’s worth raising the question.

Who Tends to Experience More Pain

Pain during and after IUD insertion isn’t the same for everyone, and some factors consistently predict a rougher experience. The biggest one is whether you’ve had a vaginal delivery before. In a study comparing pain scores during insertion of a hormonal IUD, women who had never been pregnant reported an average pain score of about 6.6 out of 10, compared with about 3.9 for women who had previously delivered vaginally.⁶ Women who had only had a cesarean delivery fell in between, at about 5.5. The cervical canal in someone who hasn’t had a vaginal delivery is typically tighter, making the passage of the IUD more mechanically difficult and more painful.

Difficulty of the insertion itself also matters. A regression analysis from the same study found that about 30% of the variability in pain scores could be explained by just two factors: never having had a vaginal delivery and the provider rating the insertion as difficult.⁶ A “difficult” insertion usually means the cervix was resistant to dilation or the IUD was hard to position correctly, and each extra manipulation adds to the pain. If your insertion was described as straightforward, you’re less likely to have severe pain afterward. If it was described as tricky, a rougher recovery makes sense.

Displacement, Expulsion, and Perforation

Sometimes IUD pain isn’t about normal adjustment at all. The device can shift out of its correct position, and when it does, the pain often has a different character: sharper, more one-sided, or suddenly appearing weeks or months after things seemed fine.

Expulsion, where the IUD partially or fully comes out of the uterus, is the most common complication. You might feel cramping, notice the strings are longer or absent, or see the device itself. Expulsion rates vary by study and population, but they’re not rare. One systematic review looking specifically at menstrual cup users found expulsion rates ranging from about 4% to nearly 19% across different studies, with the time to expulsion spanning from under a week to two and a half years.⁷ Menstrual cups may carry a particular risk because of the suction involved in removal, but expulsion can happen to anyone, especially in the first few months.

Perforation is much rarer but more serious. This occurs when the IUD pushes through the uterine wall, either partially or completely. The incidence is roughly one in a thousand insertions.⁸ Perforation can happen at the time of insertion or develop gradually over the following weeks. Some research has found a possible association between breastfeeding at the time of insertion and perforation risk, though a clear causal link hasn’t been established.⁸ Symptoms can include sudden severe pain, pain that persists and doesn’t improve, or loss of the IUD strings on self-check. Partial perforations may cause lower-grade but persistent discomfort that’s easy to dismiss as “still adjusting.”

Infection in the Weeks After Insertion

The act of inserting an IUD temporarily introduces bacteria from the lower genital tract into the normally sterile uterine cavity. This creates a window of elevated infection risk. Research has found that the risk of pelvic inflammatory disease (PID) is roughly six times higher in the first 20 days after insertion compared to baseline.⁹ After that initial window, the risk drops back to the general population level, assuming no sexually transmitted infection is present.

PID pain feels different from normal cramping. It tends to be accompanied by fever, unusual or foul-smelling discharge, pain during sex, or tenderness when your lower abdomen is pressed. If you develop these symptoms in the first few weeks after insertion, contact your provider promptly. Early PID is treatable with antibiotics, but untreated infection can damage the fallopian tubes and affect future fertility. This is one reason providers typically screen for chlamydia and gonorrhea before or at the time of IUD placement.

Ectopic Pregnancy and IUDs

IUDs are extremely effective at preventing pregnancy, but no contraceptive is perfect. When a pregnancy does occur with an IUD in place, there’s a disproportionate chance it will be ectopic, meaning the fertilized egg implants outside the uterus, usually in a fallopian tube. The IUD dramatically reduces the likelihood of an intrauterine pregnancy, but it doesn’t provide the same level of protection against ectopic implantation.¹⁰

An ectopic pregnancy is a medical emergency. Symptoms include sharp, localized pelvic pain (often on one side), vaginal bleeding that’s different from your normal period, dizziness, or fainting. Case reports describe patients presenting with a correctly positioned IUD and a ruptured ectopic pregnancy requiring emergency surgery.¹⁰ The absolute risk is very low because IUDs prevent the vast majority of pregnancies. But if you have sudden one-sided pain and suspect you could be pregnant, don’t assume the IUD means you’re protected. Get evaluated.

When to See a Doctor

Most IUD pain resolves on its own within weeks to a few months. But certain patterns warrant a visit to your provider sooner rather than later:

• Sudden severe pain: Pain that appears abruptly, particularly if it started well after the insertion, could signal perforation, expulsion, or ectopic pregnancy.
• Pain with fever or unusual discharge: This combination suggests infection and needs prompt evaluation, especially in the first three weeks after placement.
• Pain that’s getting worse instead of better: The expected trajectory is gradual improvement. Pain that plateaus at a high level or escalates after the first month isn’t typical adjustment.
• Missing or changed strings: If you can’t feel your IUD strings or they feel significantly shorter or longer than before, the device may have shifted. Pain in this context reinforces that something has moved.
• One-sided pelvic pain with a missed period: Even with an IUD, this combination should be evaluated to rule out ectopic pregnancy.
• Pain during sex: Deep pain during intercourse that wasn’t present before can indicate the IUD has migrated or is malpositioned.

Your provider can check the IUD’s position with a pelvic exam or ultrasound, run tests for infection, and determine whether the device needs to be adjusted or removed. Don’t talk yourself out of seeking care because you think IUD pain is just something you have to endure.

What Actually Helps With the Pain

Pain management for IUD insertion has been the subject of quite a few trials, and the honest takeaway is that nothing works as dramatically as most people hope. A scoping review of pain interventions in women who haven’t had children found that oral painkillers, lidocaine, and cervical-softening drugs like misoprostol all showed some benefit, with prostaglandins and lidocaine gel appearing to have the most clinically meaningful effect.¹¹

But individual trials often tell a more muted story. One randomized trial testing intrauterine lidocaine combined with naproxen found no meaningful difference in pain scores compared with placebo.¹² Another trial found that diclofenac combined with lidocaine gel did produce statistically lower pain scores during copper IUD insertion in women who had previously given birth, but the researchers themselves noted the reduction lacked clinical significance.¹³ In plain terms: the numbers moved, but probably not enough for you to actually feel the difference.

This is a genuine gap in reproductive healthcare. The evidence for strong, reliable pain control during IUD insertion remains thin, particularly for people who haven’t had vaginal deliveries and are likely to experience the most pain. Some providers now offer stronger options like cervical nerve blocks or even brief sedation for patients with high anxiety or previous traumatic insertion experiences. If you’re planning an insertion and concerned about pain, ask your provider specifically what they offer and push for more than “take some ibuprofen beforehand,” because the data suggest that alone probably won’t be enough for many people.

The Role of Timing and Cycle

Many providers recommend scheduling IUD insertion during or just after your period, when the cervix is naturally slightly more open and the uterine lining is thinner. While this can make the procedure technically easier, it’s not an absolute requirement, and some research suggests the difference in pain is modest. Still, if you have the flexibility to choose, timing your appointment for the first week of your cycle is a reasonable, low-cost way to potentially reduce discomfort.

Beyond the menstrual cycle, timing matters in another sense: how long you’ve been living with pain. The adjustment period for an IUD is real, and some cramping in the first one to three months doesn’t mean anything is wrong. But there’s a difference between patient optimism and ignoring a problem. If you’re six months out and still taking painkillers regularly before your period because of your IUD, that’s not normal adjustment. Persistent pain beyond three to six months deserves investigation, even if the IUD is in the correct position on ultrasound, because pain that an imaging study can’t explain isn’t pain that doesn’t exist. It might mean the device size is wrong for you, or that your body simply isn’t tolerating the device well, and removal might be the right call.