Drug Info

Do IUDs (like Mirena) cause weight gain?

Cropped SingleCare logo By | January 24, 2020
Medically reviewed by Anis Rehman, MD

Like all medications, birth control can have side effects. They’re important to when choosing the method that’s right for you. Birth control side effects may include acne, breakthrough bleeding, mood changes, and more. Weight gain is a common concern among women choosing birth control, but it’s a misconception that IUDs cause weight gain. To answer some frequently asked questions about IUD weight gain, we talked to Christina Madison, Pharm.D., FCCP, BCACP, AAHIVP, founder of The Public Health Pharmacist and clinical researcher of women’s health.

What is an IUD?

An IUD, or intrauterine device, is a small, T-shaped plastic device placed in the uterus to prevent pregnancy. With less than 1% risk of pregnancy each year, IUDs are the most effective form of birth control available. IUDs are a great choice for those who often forget to take their daily birth control pills. After insertion, an IUD lasts anywhere from three to 12 years. It can be used by women of all ages, according to the CDC. They are also a reversible contraception option, allowing you to go back to regular fertility once your IUD is removed.

There are two types of IUD products: copper and hormonal. While both are effective in preventing pregnancy, there are some key differences to keep in mind. 

Copper IUDs

Copper IUDs are hormone-free. They use plastic and copper coil instead of levonorgestrel. Copper is a natural spermicide, killing sperm before it can reach an egg. Copper IUDs, like ParaGard, can be used for up to 12 years.

Hormonal IUDs

Sometimes referred to as intrauterine systems, hormonal IUDs release small amounts of a progestin hormone called levonorgestrel into the uterus, which prevents sperm from reaching and fertilizing an egg. These IUDs can last anywhere from three to seven years. 

One of the most common hormonal IUD brands is Mirena, manufactured by Bayer. Mirena prevents pregnancy for up to five years but may remain effective for up to seven years. 

The cost of Mirena varies, but Bayer recently reported that 95% of women are covered with little to no out-of-pocket costs. The list price of Mirena is $953.51, which comes out to about $15 per month over five years. If your insurance doesn’t cover it, there are Mirena coupons available. 

Other common brands include Skyla, Liletta, and Kyleena. Each hormonal IUD brand is different, so be sure to consult with your OB-GYN on which is right for you.

What are the side effects of an IUD?

Both hormonal and copper IUDs do much more than prevent pregnancy. For example, Mirena treats heavy bleeding, which benefits those who experience endometriosis-related pain. ParaGard, the copper IUD, is also used as emergency contraceptive since it begins working immediately.

Side effects of intrauterine dosage forms, like the Mirena IUD, are typically less severe than those seen with oral contraceptives, according to Dr. Madison.

While IUDs are 99% effective, there are some common side effects to be mindful of, including:

  • Cramping and back pain after placement
  • Irregular bleeding and spotting during your menstrual cycle
  • Irregular periods, which may become lighter or even stop
  • Ovarian cysts, which usually disappear
  • Heavy menstrual bleeding or longer periods with copper IUDs

Rare but serious side effects of IUDs could include the following:

  • Potential risk of pelvic infection within 20 days after insertion
  • The IUD may slip or move and will need to be taken out by a professional
  • Expulsion of the device from the uterus

Mirena side effects

Possible side effects of IUDs vary from patient to patient, and by the type of IUD used. The Mirena IUD may have additional, hormone-based side effects like:

  • Headaches
  • Acne
  • Breast tenderness
  • Mood swings
  • Nausea
  • Fatigue

Since Mirena and other hormonal IUDs use the progestin hormone instead of estrogen, some patients may experience weight gain or hair loss due to lower estrogen levels. Mirena weight gain and hair loss are uncommon and may be related to a number of other health issues, like stress or other illnesses.

“Benefits of using these highly effective and long-acting products outweigh the risk of potential side effects,” says Dr. Madison, but make sure to consult with your doctor to determine if an IUD is the right option for you.

IUD weight gain

The majority of IUD users do not experience weight gain. Copper, non-hormonal IUDs do not cause any weight gain, whereas about 5% of patients using hormonal IUDs report  weight gain. Since Mirena is a hormonal IUD, Mirena weight gain is possible, if unlikely.

“The perception of weight gain from these products is widely thought of but has not been substantiated,” says Dr. Madison. “There was no difference in body weight or composition seen among [IUD] products after 12 months of continuous use.” While you may have some weight gain after getting your IUD, it should subside.

Weight gain can happen with hormonal IUDs due to the hormone, progestin, used. Any IUD weight gain is likely not an increase in body fat, but instead an increase in water retention. The hormone progestin may increase water retention that causes bloating, typically adding about five pounds. The amount of weight gained will vary from patient to patient, but any water retention will likely go down three months post-insertion.

It’s important to know that gaining any weight post-insertion is likely due to the patient’s lifestyle as opposed to the IUD itself. Many American women naturally gain two pounds each year, entirely unrelated to any hormonal contraceptives, according to Yale Medicine.

Consider making some lifestyle changes to avoid weight gain after getting an IUD. Exercising regularly, healthy eating, and all other common weight loss methods should minimize the chances of any weight change after getting an IUD.

Should bloating not subside three months after insertion, consider speaking with a healthcare professional about other options. Copper IUDs, like Paragard, have not been linked to IUD weight gain, making them a great alternative.

What birth control doesn’t cause weight gain?

Should an IUD prove to be not the best birth control method for you, there are plenty of other contraceptive options to consider. Consult your healthcare provider about what would work best for you. Some common birth control options include:

Hormonal birth control methods get a bad reputation for causing weight gain. Any weight gain reported while taking birth control is likely natural, like aging or your metabolism slowing down.

Only one form of birth control has been linked to weight gain, and that’s the injection Depo-Provera. If you’re looking to avoid weight gain, stay away from any injectable contraceptive. These injectables have been shown to activate signals that control hunger, resulting in weight gain in some patients.

As you consider other birth control options, keep in mind that some, like the pill, injections, the patch, and vaginal rings, have 10% yearly failure rates due to human error. 

“Choosing the best contraceptive product is very individualized,” says Dr. Madison, so make sure to speak openly and honestly with your gynecologist about which birth control method is right for you.