A diaphragm is a form of birth control that is a shallow, bendable cup made of soft silicone that is inserted into the vagina to cover the cervix during sex. It works as a barrier that covers the cervix, stopping sperm from joining an egg, and must be used with spermicide to be most effective. Spermicide has chemicals that stop sperm from moving so they cant get to an egg, and the diaphragm keeps the spermicide in place, near the cervix. A diaphragm should be replaced at least every 2 years and checked regularly for holes or weak spots. It is important to note that a diaphragm does not protect against sexually transmitted infections (STIs), and couples having sex must always use condoms along with the diaphragm to protect against STIs. Some possible side effects of using a diaphragm include irritation of the vagina and surrounding skin or an allergic reaction to the spermicide, strong odors or vaginal discharge if the diaphragm is left in too long, a higher risk for urinary tract infections (UTIs), and toxic shock syndrome if the diaphragm is left in too long.