A contraceptive diaphragm is a barrier method of contraception where a circle of silicone is placed inside the vagina before sex to cover the cervix so sperm cannot enter into the uterus (womb). A diaphragm must be used alongside spermicide, which basically kills any sperm. The diaphragm must be left in place for at least 6 hours after sex, then removed and washed prior to being used again. When used correctly, they are around 92-96% effective, so they are less effective than many other contraceptive options.
Learn more about diaphragm.
Remember, this method of contraception is only effective in preventing pregnancy, to protect yourself against STIs and BBVs, condoms should also be used, which can be accessed for free via the Lanarkshire C Card Scheme.