IUD, also known as a coil, stands for intrauterine device. - "intra" meaning within, and "uterine" meaning of the uterus. An IUD is about 1.5 inches long and it's inserted into your uterus to prevent pregnancy. They are 99% effective.
There are 2 types of IUDs, ones made out of metal, and ones that release hormones similar to those found in oral contraceptives (the Pill.) Most of the metal IUDs have a plastic T-shaped frame that is wrapped with copper. The copper is believed to have spermicidal effects, which is one reason why it works. You can wear this one for up to 10 years.
IUD's that release hormones are also T-shaped, but they are made out of plastic. The hormones make your cervical fluid thick and tacky, making it difficult for sperm to swim in, so they never make it to the egg, so therefore they can't fertilize it. You can wear this one for up to 5 years.
Both kinds of IUDs have little plastic strings attached at the bottom that hangs down past the cervix. The string is not visible and it won't cause any problems during intercourse. The string is a safety check so you can check to make sure your IUD is still in place.
An IUD has to be fitted inside and removed from the uterus by a doctor or nurse practitioner. IUDs don't stop you from ovulating, so you still get your period, but your flow may become shorter or lighter, or may even stop altogether. Some women complain that their periods are irregular when using an IUD as birth control.
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When something foreign is inside your uterus, your body produces white blood cells, or leukocytes to defend itself. These white blood cells attack any sperm or eggs that may find their way into your uterus. Even if an egg does get fertilized, the white blood cells will attack it. For this reason, people who are against abortion, believing that life begins at conception, are against the IUD.
Fit's Tips: An IUD is great if you are looking for hassle-free birth control. In no way does it prevent against STDs, so that's why it's great to use if you are in a long-term relationship with someone you know is disease-free. That is why they are most often recommended for women who are married and done having children. Ask your doctor to discuss if an IUD may be right for you.