STI's are infections that are transmitted through sexual contact. You can get an STI by sexual intercourse but also through oral sex, anal sex or contact with bodily fluids such as sperm, saliva, blood, and vaginal discharge.
Some of the things that increase a person's chances of getting an STI are:
Lots of sexual partners - People who have sexual contact with many different partners are more at risk than those who stay with the same partner.
Unprotected sex - Latex condoms are the only form of contraception that reduce your risk of getting an STI, and must be used every time. The pill, implants, coils, and other contraceptive methods may help prevent pregnancy, but they don't protect a person against STIs.
The best way to protect yourself from getting an STI is using condoms.
Everyone who has sex is at risk of an STI and you can’t always tell if someone has an STI because most people have no symptoms or signs of an infection. If you have had unprotected sex, it might be worth having a check up.