An intrauterine device (IUD) is a small T-shaped plastic device that is placed in the uterus to prevent pregnancy. A plastic string is attached to the end to ensure correct placement and for removal. IUDs are an easily reversible form of birth control, and they can be easily removed. However, an IUD should only be removed by a medical professional.
Currently in the United States, 2 types of IUDs are available: copper and hormonal. Approximately 2% of women who use birth control in the United States currently use IUDs. The most recently introduced hormonal IUD is the levonorgestrel intrauterine system (LNG IUS or Mirena). Worldwide, IUDs are the most inexpensive long-term birth control method available.
How an IUD Works
Hormonal and copper IUDs work in different ways. With a copper IUD, a small amount of copper is released into the uterus. This type of IUD does not affect ovulation or the menstrual cycle. Copper IUDs prevent sperm from being able to go into the egg by immobilizing the sperm on the way to the fallopian tubes. If an egg does become fertilized, implantation on the wall of the uterus is prevented because copper changes the lining of the uterus.
With hormonal IUDs, a small amount of progestin or a similar hormone is released into the uterus. These hormones thicken cervical mucus and make it difficult for sperm to enter the cervix. Hormonal IUDs also slow down the growth of the uterine lining, making it inhospitable for fertilized eggs.
Placement of the IUD
Before an IUD is placed, a physical examination is important to make sure that the reproductive organs are normal and that no infections are present. The clinician will ask about medical and lifestyle history. Being open and honest is important when answering these questions. IUDs are not appropriate for every woman.
Before the IUD is placed, a woman should discuss any questions she has with her clinician. The clinician will also provide a consent form with detailed information about the IUD. The woman should make sure to read this form carefully and understand it before signing.
An IUD can be placed during an office visit and remains in place until a medical professional removes it. It can be inserted at any phase of the menstrual cycle, but the best time is right after the menstrual period because this is when the cervix is softest and when women are least likely to be pregnant. Women may be instructed to take an over-the-counter pain reliever an hour before insertion to prevent cramps. Women may also be given an antibiotic to prevent possible infection associated with insertion; however, some studies disagree about the benefit of antibiotics.
To place the IUD, a speculum is used to hold the vagina open. An instrument is used to steady the cervix and uterus, and a tube is used to place the IUD. The arms of the T shape bend back in the tube and then open once the IUD is in the uterus. Once the IUD is in place, the instruments are withdrawn. The string hangs about an inch out of the cervix but does not hang out of the vagina.
Cramps may be uncomfortable during insertion, and some women feel dizzy. Breathing deeply and trying to relax should prevent these problems. Women may want to have someone with them to drive them home after IUD insertion.
Once the IUD is placed, women can return to normal activities such as sex, exercise, and swimming as soon as they are comfortable. Strenuous physical activity does not affect the position of the IUD. Women can also use tampons as soon as they wish after an IUD is placed.
Removal of the IUD
Women should never try to remove an IUD themselves. Serious damage can result. A clinician can usually remove an IUD very simply by carefully pulling the string ends at a certain angle. This causes the IUD arms to fold up and the IUD to slide out through the cervix. If the IUD is being replaced, a new one can usually be inserted immediately.
Rarely, the cervix may need to be dilated and a grasping instrument is used to free the IUD. If this occurs, a local anesthetic is used.
Very rarely, surgery may be necessary. Women may require hospitalization if an incision is required to remove an IUD.