An IUD is a small, plastic T-shaped device that a doctor inserts through your vagina and into your uterus. Insertion is quick and mostly painless, although some people have mild cramping for a short time afterward. IUDs are very effective, preventing pregnancy about 99% of the time. There are two different types of IUDs:
Hormonal IUDs.
The copper IUD.
The hormonal IUD releases small amounts of hormones for three to eight years. It works by thickening the mucus in your cervix, making it unfriendly to sperm. The sperm then can’t move well enough to fertilize an egg. Hormonal IUDs also thin the lining of your uterus that sheds during your period each month. That’s why many women have lighter periods when they’re using a hormonal IUD — and why some don’t get their periods at all. The copper IUD doesn’t have hormones. Instead, copper ions repel sperm, preventing them from reaching an egg to fertilize. This type of IUD prevents pregnancy for up to 10 years. A copper IUD might cause heavier bleeding or more painful periods initially. Your periods should return to normal after the first few months. But there is a potential these side effects can last. Unlike other long-lasting forms of birth control, like the pill or an implant, IUDs usually do not affect ovulation. When you ovulate, you release an egg each month. That usually still happens with an IUD, but sperm can’t fertilize your egg.