A custom-fitted cervical cap has some advantages over the diaphragm. It fits more snugly, is more comfortable, and, because of a small one-way valve in its center, it permits the flow of menstrual blood and mucus, yet prohibits the travel of sperm from the vagina to the uterus. Because of the possible risk of toxic shock syndrome, the cervical cap should not be worn for more than 48 hrs. Jellies, Creams, Vaginal Film, Suppositories, and Foams. Nonoxynol 9 is the active agent in most spermicidal products in the United States.
Consistent use is the most important factor in minimizing failure rates with spermicides.
Nonoxynol 9 may also decrease the risk of sexually transmitted diseases, but it can cause vaginal irritation in some individuals. There are a number of contraceptive jellies, creams, and aerosol foams that are more powerful than those used with diaphragms and are made to be used without any mechanical device. This is a thin polyurethane sheath containing two flexible rings. One ring lies inside at the closed end of the sheath and serves as an insertion mechanism and internal anchor. The other ring forms the external open edge and remains outside of the vagina.