IUDs (Intrauterine Devices) are a long acting, highly effective and reversible birth control method. An IUD is a small, T-shaped device that is inserted into the uterus to prevent pregnancy for up to 10 years. The IUD itself does not increase the risk of STIs, but it also does not prevent them.
So if you are having condomless sex with an IUD, your risk of pregnancy is reduced, but not your risk of STIs.
Regardless of your method of birth control, if you’re sexually active you can take steps to prevent STIs. This may include getting tested routinely, encouraging you partner(s) to also get tested, accessing STI treatment if necessary and using barriers like external condoms, internal condoms, and sex dams.