Birth Control Intrauterine Devices (IUDs)
Francisco Talavera, PharmD, PhD
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.
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Patient Comments & Reviews
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