How effective is the intrauterine device or system (IUD/IUS)?

How effective is the intrauterine device or system (IUD/IUS)?

All types of intrauterine devices and intrauterine systems (both hormone-based and copper-based) provide 99% protection against pregnancy when fitted correctly, making them among the most effective contraceptives available.

 

Intrauterine devices do not protect against sexually transmitted infections (STIs).