Does the diaphragm protect from STIs?

No, the diaphragm does not protect against sexually transmitted infections (STIs). The best way to prevent STIs if you’re having sex is using a condom or internal condom. Dental dams, gloves, some vaccines (HPV and hepatitis B vaccines) and daily medications, such as PrEP for the prevention of HIV also offer STI protection. If you’re concerned about both pregnancy and STIs, doubling up with the diaphragm and condoms is a great option.