You need to insert a vaginal suppository at least 10 minutes before intercourse to allow it to dissolve, but no more than 30 minutes in advance, or it will lose its effectiveness. Each act of intercourse requires additional spermicide. Wait at least 6 hours before douching. Using a panty liner will keep you more comfortable if the spermicide leaks out of your vagina. Pros and cons.
Spermicides are readily available without a doctor's prescription and are easy to use.
Look for those that contain nonoxynol 9, which gives added protection against sexually transmitted disease. The biggest drawback of spermicides is their low effectiveness when used alone. This is particularly true of jelly and cream, but even foam and suppositories prevent pregnancy only about 79 percent of the time. For this reason, couples who need highly effective contraception should combine spermicide with another method, such as a condom, diaphragm, or cervical cap. Some people are allergic to spermicides.