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What is an IUD?

An IUD (intrauterine device) is a small T-shaped device which is inserted into the uterus by a trained health care provider. It is as effective as a tubal ligation in preventing pregnancy (over 99% effective), but is easily reversible.  IUDs work by preventing sperm from fertilizing an egg.

There are two types available: the non-hormonal ParaGard, which re­leases copper into the uterus, and the hormone containing IUDs, (Mirena, Kyleena, Liletta, and Skyla), which re­lease a synthetic progesterone called levonorgestrel into the uterus.  All have two strings that extend into the vagina which can easily be checked to ensure the IUD is in place.  The strings are not uncomfortable for the woman or her partner.

What are the advantages of IUDs?

  • Long lasting protection for 3-10 years, depending on the type
  • Highly effective
  • Convenient– after insertion, you only need to remember to check the strings once a month
  • Cost effective over time, although initial cost is high if you don’t have insurance
  • Safe– IUDs are the most commonly used, re­versible method worldwide
  • Easily reversible– when you are ready to stop using the IUD, your clinician removes it by pull­ing on the strings.  Fertility is immediately re­stored. 


 What are the disadvantages?

  • Menstrual problems - for the first several months irregular bleeding is common for all IUDs.  Thereafter, the hormone-releasing IUD’s decrease menstrual flow and cramping while ParaGard increases it. 
  • Cramping and pain with insertion
  • Small increased risk of PID (pelvic inflammatory disease) immediately after insertion
  • PID can occur if you are exposed to gonorrhea or chlamydia while using an IUD. If PID goes untreated, it can result in infertility or ectopic pregnancy.
  • Perforation of the wall of the uterus.  Although the risk is very low (about 1/1,000), a surgical procedure is needed to retrieve the IUD. 
  • Expulsion of the IUD in which the IUD sponta­neously “falls out.”  This is more common for women who have never been pregnant. It happens in 2-5% of women.
  • While IUDs protect against both uterine and tubal pregnancies, the protection against tubal pregnancy is not as complete.  An IUD failure is more likely to be a tubal pregnancy.
  • IUDs do not protect against sexually transmitted infections.


When can an IUD be inserted?

IUDs can be inserted at any point in the cycle, includ­ing during the period, as long as there is no chance you could be pregnant.

What can I expect during the insertion?

The IUD insertion only takes a few minutes, but it does cause intense cramping for some women.  You will be instructed to take ibuprofen before the inser­tion.  For most women, the intense cramps subside rapidly after the insertion. You may have milder cramps for up to several days after the insertion.

After I have an IUD inserted, what should I report to my health care provider?

You will need to be examined if you can’t feel the strings, if you develop abdominal pain, abnormal vag­inal discharge, an unexplained fever, or if you have symptoms of pregnancy.

Can I use an IUD if I’ve never been pregnant?

Yes, although there may be a higher rate of expulsion.

Who should not use an IUD?

Women who are not in a mutually monogamous relationship are not ideal IUD candidates, unless they are committed to always using condoms as well.

Mirena, Liletta




Length of use

5 years

3 years

    5 years

10 years


52 mg levonorgestrel, which acts locally on the uterine lining, but causes minimal changes in blood hormone levels. 

13.5 mg levonorgesterel

  19.5 mg levonorgestrel


How it works

Levonorgestrel thickens cervical mucus and impairs sperm migration to prevent fertilization; may intermittently prevent ovulation.

Same as Mirena and Liletta; smaller size

   Same as Mirena and Liletta; smaller size

Copper inhibits sperm motility to prevent fertilization.

Effect on periods

Periods shorter and lighter; periods may be irregular or stop altogether. Good choice for treatment of heavy or painful periods

Periods shorter and lighter, irregular.

 Periods shorter and lighter; periods may be irregular or stop altogether.

Makes periods heavier and crampier

Ovarian cyst

Increased risk of  ovarian cysts most of which often resolve spontaneously.

Increased risk of  ovarian cysts most of which often resolve spontaneously.

 Increased risk of  ovarian cysts most of which often resolve spontaneously.

No effect




American College of OB/Gyn: FAQs about long acting contraception

Bedsider: Bedsider: IUDs