IntraUterine Devices (IUDs)

Intrauterine devices are small devices that are inserted into the uterus to prevent pregnancy. There are two kinds: copper based, and hormone based. For information on hormone based devices, see our page on IntraUterine Systems.

Copper IntraUterine devices prevent pregnancy by changing the lining of the uterus. It becomes hostile to sperm and eggs, and kills both.

There is only type of copper IUD available in the US, Paragard T 380A. There are seven currently available in Britain. Paragard, like most IUDs, is shaped like a T.

IUDs can be left in the body for between 5-10 years. They are a highly effective form of birth control.

IUDs can also be used as a form of emergency contraception if inserted within 5 days of unprotected sex. This is helpful for women who cannot use hormonal emergency contraception. If this is the case, the IUD can be left in for the desired length of time, or taken out after the following period.

Copper IUDs are effective as birth control immediately after insertion. Hormonal IUSs take effect in seven days.

Copper IUDs can cause an increase in menstrual flow and duration; hormonal IUSs can decrease menstrual flow. It is not unusual to have cramps for the first few months with an IUD. This can be treated with regular pain medication.

Vas-occlusion is currently being studied as a way for men to have long-term but reversible birth control.

See our pages on IUDs: