Spermicide is a contraceptive substance that eradicates sperm and is inserted vaginally prior to intercourse to prevent pregnancy. As a contraceptive, spermicide may be used alone. However, the pregnancy rate experienced by couples using only spermicide is higher than that of couples using other methods. Spermicides have a failure rate of 18% per year when used correctly and consistently, and 29% under typical use. Usually spermicides are combined with contraceptive barrier methods such as diaphragms, condoms, cervical caps, and sponges. Combined methods are believed to result in lower pregnancy rates than either method alone. Spermicides cause irritation and according to the CDC, studies have shown that spermicides increase the risk of HIV.
The most common active ingredient of spermicides is nonoxynol-9. Spermicides containing nonoxynol-9 are available in many forms, such as jelly (gel), films, and foams, but are not recommended for use by the CDC. The World Health Organization says that spermicidally lubricated condoms should no longer be promoted. However, they recommend using a nonoxynol-9 lubricated condom over no condom at all.
Nonoxynol-9 has a number of possible side effects. These include irritation, itching, or the sensation of burning of the sex organs of either partner, and in women, urinary tract infections, yeast infection, and bacterial vaginosis. These side effects are uncommon; one study found that only 3-5% of women who try spermicides discontinue use due to side effects.
Spermicides are believed to increase the contraceptive efficacy of condoms. However, condoms that are spermicidally lubricated by the manufacturer have a shorter shelf life and may cause urinary-tract infections in women.
Concern has been raised over possible increased risk of birth defects in children conceived despite spermicide use, and also in children of women who, not yet aware of their condition, continued spermicide use during early pregnancy. However, a review in 1990 of large studies on spermicides concluded that there appears to be no increased risk of congenital anomalies, altered sex ratio, or early pregnancy loss among spermicide users.