Intrauterine Device
What is an IUD?
An IUD 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 (over 99% effective), but is easily reversible. IUDs work by preventing sperm from fertilizing an egg.
There are two types available: ParaGard, which releases copper into the uterus and Mirena, which releases a synthetic progesterone into the uterus. Both 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 5-10 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
- 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 Mirena decreases menstrual flow and cramping while ParaGard increases it.
- Cramping and pain with insertion
- Small increased risk of PID (pelvic inflammatory disease) immediately after insertion
- 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 way you could be pregnant.
What can I expect about 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 cramps subside rapidly 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 good IUD candidates.
Mirena
ParaGard
Mirena | ParaGard | |
Length of use | 5 years | 10 years |
Hormone | Levonorgestrel, which acts locally on the uterine lining, but causes negligible changes in blood hormone levels. | None |
How it works | Levonorgestrel thickens cervical mucus and impairs sperm migration to prevent fertilization; may intermittently prevent ovulation. | Copper inhibits sperm motility to prevent fertilization. |
Effect on periods | Makes periods shorter and lighter; periods may be irregular or stop altogether. | Makes periods heavier and crampier |
Ovarian cyst | 10% of women develop ovarian cysts which often resolve spontaneously. | No effect |
