Spermicides are creams, foams, gels and pessaries (tablets), which act to kill sperm on contact. The most commonly used spermicides are nonoxynol 9 and octoxinol. A pessary can be inserted high into the vagina at the opening to the womb by hand, but creams, gels and foams are usually inserted with an applicator. A spermicide should be inserted no more than 20 minutes before intercourse and a new application must be inserted before each ejaculation.
Even used strictly as directed, the failure rate of such contraceptives is high, and they are more suitable for use in conjunction with other methods (eg. diaphragm, condom) rather than on their own. Even in combination with a diaphragm or condom, spermicides have a failure rate of about 5% (ie: five out of 100 fertile women using this method of contraception for a year will fall pregnant).
Ensure hands and diaphragm are completely clean before insertion. Wait six to eight hours after sex before removing a diaphragm or using a douche. Do not retain a diaphragm for more than 24 hours.
Spermicides are safe if used accidentally in pregnancy, and safe in breastfeeding. Side effects are minimal, but uncommonly irritation of the vagina or penis may occur.