Spermicides have been used as birth control for thousands of years. Studies have recently looked at how well they work to prevent pregnancy and whether women like them. Spermicides contain an active ingredient (usually nonoxynol-9) and something to disperse the product, such as foam or vaginal suppository (pessary). This review compared how well different spermicides worked for birth control when used alone.
We did computer searches for randomized trials of spermicides used for birth control. We also wrote to researchers to find other trials.
Trials had to focus on a spermicide used alone for birth control. The product could be compared to a different spermicide, the same spermicide used with a barrier method, another dose of the same spermicide, a different base for the same product, or another type of birth control. Each study must have had data on pregnancy.
We located reports from 14 trials. The largest trial compared five different spermicides. The gel with the smallest amount of nonoxynol-9 did not prevent pregnancy as well as products with more of the same ingredient. Women liked the gel better than the film or suppository. Few differences were found in the other studies. These trials had problems recruiting women into the studies and then keeping them until the trial ended. Large losses to follow up can bias the results.