Intrauterine Device (IUD)

What is and IUD?

IUDs are small devices made of flexible plastic and are shaped like a T. There are two kinds of IUDs available in the US. The first is the ParaGard® Copper T 380A which is made of copper and may be left in place for up to 10 years. The second IUD is the Mirena® which continuously releases a progestin called Levonorgestrel and may be left in place for 3 – 5 years.

Both IUDs have a “string” or filament that is threaded through a hole in the bottom of the T. This string is made of single strand of strong plastic and does not absorb or “wick” fluid or bacteria into the uterus as a cotton string may do. The string is there to let a woman or provider know that the IUD is still in place and to allow for easier removal. If the string is shortened or can’t be found, the IUD may have moved out of placed or been expelled. If this occurs, see your provider immediately.

How does an IUD prevent pregnancy?

Once inserted the IUD works immediately to prevent pregnancy. The IUD works primarily by preventing the sperm from fertilizing an egg and by changing the cervical mucus (not advantageous to sperm). Scientists still can’t explain exactly how the IUD prevents fertilization. Some believe that the IUD affects sperm mobilization and their ability to fertilize the egg, while others believe the IUD causes the egg to move too fast through the fallopian tubes, allowing no time for the egg to get fertilized.

In the ParaGard®, the copper increases effectiveness of the IUD by affecting the behavior of the enzymes of the uterus to prevent implantation. The Mirena® has a primarily hormonal method of action: the cervical mucous is thickened, ovulation can be interrupted, and the uterine lining is altered preventing implantation.

How is the IUD inserted and removed?

An IUD can be inserted at any time and must be done by a provider. There is evidence that the best times to insert an IUD are during your menstrual cycle or midcylce. During these times your cervix is dilated making insertion easier.

For more information on insertion, visit www.plannedparenthood.org/bc/IUD.HTM.

Removal of an IUD must also be done by a provider. Do not try to remove the IUD yourself by pulling on the strings.

How effective are IUDs?

The theoretical effectiveness rate of  IUDs are 99.9% (Mirena® (Levonorgestrel)) and 99.4% (ParaGard® (copper)).  These rates are based on studies that have been done to determine how effective a method itself can be, apart from user behaviors. Actual effectiveness rates are 99.9% and 99.2% respectively, which reflectss what happens to the pregnancy rate in a group of people who do not use this method correctly some of the time and who do not use this method every time they have intercourse.

Who should use an IUD?

The ideal candidate for an IUD:

• is not at risk for contracting an STD (sexually transmitted disease)
• has had one or more children
• wants an effective, long lasting, reversible method
• has not had pelvic inflammatory disease, gonorrhea, or chlamydia in the past 12 months

Advantages of IUDs

• Nothing to do right before having intercourse
• Women who cannot use hormonal methods, can use the copper IUD
• The progestin IUDs decrease menstrual blood loss and the incidence and intensity of cramps
• IUD is easy to use
• Easily reversible
• Less risk of ectopic pregnancy
• Less bleeding and cramps with Mirena®
• Can be left in place for 5-10 years (depending on which IUD used)

Possible Disadvantages

• No protection against STDs. Use a condom if you feel you are at risk.
• If you are allergic to copper, you cannot use the ParaGard® Copper IUD
• Risk of developing Pelvic Inflammatory disease due to insertion or contraction of STD
• 2-10% will expel the IUD in the first year and may go unnoticed which could lead to pregnancy
• Heavier menstrual flow, increased cramps and spotting between periods with the ParaGard®
• Irregular bleeding/amenorrhea with Mirena®
• Possible risk of infection following insertion
• Infertility
• Uterine puncture ( one to three of every 1000 women)

Warning Signs

Remember PAINS:

P: Period late (pregnancy), abnormal spotting or bleeding
A: Abdominal pain, pain with intercourse
I: Infection exposure (any STD), abnormal discharge
N: Not feeling well, fever, chills
S: String missing, shorter or longer

Availability

Currently not available at the Duke Student Health Center. Check with Duke Family Medicine (Pickens), the local health department or Planned Parenthood for availability.

Sources:
Robert A. Hatcher, et al. Contraceptive Technology, 17th ed. (New York: Irvington Publishers, Inc., 1998)
Planned Parenthood – www.plannedparenthood.org