Somewhat similar to the diaphragm, the cervical cap is a small rubber dome that covers the cervix and holds spermicide against the cervical opening. The difference is that, instead of being anchored by the vaginal muscles and pubic bone, the snugly fitting cap is held in place by surface tension or suction. In women who have delivered a baby, however, the rate rises to about 26 percent. Pregnancy and childbirth cause the cervix to become softer and more pliable, and hence less capable of staying in place. How to use it.
Most women find that it's a little harder to insert and remove a cervical cap than a diaphragm.
It may take a little practice and patience until you get it right. After your doctor fits you for a cap, be sure you understand the steps for insertion and removal, as well as how to check for proper fit. Inserting the cap. To use the cap, place a small amount of spermicide in the dome, filling it about a third of the way. Don't use too much, and don't put any on the rim of the cap.