8 IUD side effects to know — from cramping to changes in your period

An intrauterine device, better known as an IUD, is a form of birth control that is inserted into the uterus, where it sits above the cervix. 

There are two forms of this contraception: hormonal and copper (non-hormonal). Both have side effects, although they can differ. 

Here's what you need to know about IUD side effects and how to reduce them. 

Hormonal IUD side effects

There are four brands of hormonal IUDs — Mirena, Skyla, Kyleena, and Liletta. All use a hormone called progestin, which prevents fertilization by thickening the cervical mucus, thinning the uterine walls, and possibly stopping ovulation. These IUDs last different lengths of time, between three to seven years. 

There are specific side effects to keep in mind when considering the hormonal IUD: 

Irregular bleeding

It's very common to have irregular bleeding for the first few months of a hormonal IUD. You might bleed for three weeks, stop for a few days, then start bleeding again, and you may experience spotting, says Dr. Laura Laursen, an OB-GYN at Rush University Medical Center. 

After those three to six months, the bleeding should level out. But if you're bleeding through a pad an hour, consult your doctor. 

Lighter or absent periods

For those on hormonal IUDs, monthly periods and cramping may lighten or stop altogether. While on the Mirena IUD, as many as 50% of users stopped having their periods after 3 years. 

If you experience heavy periods, your OB-GYN might suggest getting a hormonal IUD. In fact, the FDA approved the Mirena IUD as a treatment for heavy periods.

Hormonal side effects

People with a hormonal IUD may experience an increase in acne, headaches, breast tenderness, and mood swings due to an increase in hormones.

While hormonal IUDs were once thought to only affect the uterus, a 2021 study found higher amounts of certain hormones in the breast tissue of women with IUDs. This suggests that hormonal IUDs can affect other parts of the body, similar to the birth control pill. 

Because of this, there may be a small chance of experiencing weight gain after getting a hormonal IUD. In a large 2020 study, participants with hormonal IUDs gained twice as much weight as participants with copper IUDs after 60 months. However, the average amount of weight gained was small (around 3 pounds).

But because IUDs release just 20% of the progestin found in oral contraceptives, these side effects are much less common. Additionally, hormonal IUDs don't contain the hormone estrogen, reducing the chances of hormonal side effects. 

Copper IUD side effects

Copper IUDs do not contain any hormones and instead use copper to redirect the sperm away from the egg. They can last for 10 or 12 years. Paragard is the only type of copper IUD available.

When considering a copper IUD, there is a different set of side effects to be aware of: 

Heavy bleeding 

You may experience heavier or longer periods while on the copper IUD, says Dr. Katherine Pocius, the medical director of Family Planning for the Vincent Obstetrics and Gynecology Service at Massachusetts General Hospital. Once your body adjusts to the IUD — usually after three to six months — this side effect should resolve. 

If your heavy bleeding does not stop, you can consult your doctor about starting birth control pills alongside the IUD, says Laursen. The hormones in the birth control pill can help regulate your period. 

A 2012 review found that NSAIDs, like ibuprofen (Advil), can effectively treat bleeding irregularities associated with copper IUDs. They may also prevent bleeding in new copper IUD patients. 

Intense period cramping

You may experience worsening cramps with a copper IUD as well, says Pocius. You can treat the cramps with heating pads and ibuprofen, but consult your doctor if this doesn't relieve pain. 

Serious, but rare, side effects or complications of IUDs

There are some more serious side effects with both the copper and hormonal IUD. While uncommon, these complications require medical attention. 

Pelvic inflammatory disease (PID)

IUD users are at a higher risk of pelvic inflammatory disease — a bacterial infection of the reproductive organs — for four weeks after insertion. Symptoms include: 

• Pelvic pain when urinating or during sex
• Abnormal vaginal discharge
• Fever

However, infection is very rare. A 2018 review found the likelihood for contracting PID after IUD insertion is less than 1%. 

IUD expulsion 

This is when an IUD falls out completely or partially. According to the American College of  Obstetricians and Gynecologists, expulsion happens in 2% to 10% of IUD users, depending on the type of IUD. This is most common in the first three months after insertion. You are more likely to expel a hormonal IUD if you are:

• Under 20 and have a hormonal IUD 
• Under 25 and have a copper IUD
• Have intense period pain or heavy periods
• Previously expelled an IUD
• Have never been pregnant 

If there's a lot of pain all of sudden or if there's a change in how much you're bleeding, then call your provider, says Laursen. 

Some users may not notice, only to find the IUD in their underwear or in the toilet. If your IUD does fall out, consult your doctor about reinsertion or other options. 

Uterine perforation

This is when the IUD punctures a hole in the uterus and escapes into the pelvic or abdominal cavity, says Pocius. A small 2013 study of patients with copper IUDs who experienced uterine perforation found that about 70% of users experienced symptoms while 30% did not. 

Signs can include: 

• Abnormal bleeding 
• Abdominal pain 
• Missing IUD threads 
• Pregnancy 

The likelihood that a user will experience a uterine perforation is one in 1,000. However, if it does occur, it will require surgery to remove the IUD. 

IUD insertion side effects

The insertion process lasts only a minute or two for both forms of IUDs. People normally feel pain or some cramping during the process, and there may be some side effects after the procedure. Here are some of the most common:

• Cramping: In the first few days after insertion, the biggest side effect is cramping, says Laursen. This cramping can be treated with heating pads or painkillers. If cramping is not relieved by these methods, talk to your doctor. The IUD may have been incorrectly inserted. 

• Irregular bleeding: Both types of IUDs will cause irregular bleeding and spotting after the procedure. Those with the copper IUD may experience irregular bleeding for a few weeks, according to Laursen, while the hormonal IUDs may cause irregular bleeding for three months.

• Dizziness or nausea: Some people may be dizzy or nauseous after the procedure, says Pocius, but these symptoms should go away in a half-hour. 

To prepare for the procedure and reduce any uncomfortable side effects: 

• Take an over-the-counter painkiller before the procedure to help with cramping.
• Eat a snack and drink water beforehand to prevent dizziness after the procedure. 
• Cancel plans ahead of time. Some people may feel completely fine after the procedure, but others may need to take it easy and rest. 

Some doctors suggest avoiding penetrative sex for 48 hours after insertion to keep from displacing the IUD.

Insider's takeaway

While an IUD is an incredibly safe form of contraception for most people, it's important to consider the side effects. 

Both the hormonal and copper IUD may cause spotting, irregular bleeding, and cramping after the procedure. Hormonal IUDs may cause your period to lighten or disappear, while the copper IUD may cause a heavier flow and more intense cramping. 

Most of these side effects will diminish over time and can be treated with heating pads and pain killers, but it is always important to consult your doctor if any side effects seem serious, painful, or surprising.