The hormonal IUD (sold as MirenaTM) is a small plastic T-shaped device that contains progestogen. This is a synthetic version of the naturally occurring hormone progesterone. The device has a coating (membrane) that controls the release of progestogen into the uterus. Like the copper IUD, it has a fine nylon string attached to the end to make checking and removing it easier
IUDs, both copper and hormonal, do not provide protection from STIs. It is, however, important to practise safer sex.
The best way to reduce the risk of STIs is to use barrier protection such as condoms with all new sexual partners. Condoms can be used with IUDs when having intercourse to help prevent the spread of infections.