Effectiveness Overview Spermicides are chemical products inserted in a woman's vagina before sex that inactivate or kill sperm. Of these, nonoxynol-9 is the most common. Spermicides often are used as a temporary method while waiting for a long-term method or by couples who have intercourse infrequently. Many breastfeeding women who need contraception use spermicides since they increase vaginal lubrication, can be used immediately after childbirth, and have no hormonal side effects.
Some condoms also come lubricated with spermicide.
When used alone, spermicides provide some contraceptive protection, but are best when used with a barrier method to prevent pregnancy. For information about microbicides, see the Contraceptive Research and Development page. Data presented at the XIII International AIDS Conference indicated that frequent use and higher doses of N-9 can lead to tissue trauma, thus possibly increasing the risk of infection. These latest data show that N-9 is ineffective against HIV transmission among women who use large amounts of spermicide on a frequent basis.