How effective is contraceptive gel?

Varies. The theroretical or "perfect" use of a contraceptive gel or cream should approach 85-90 % but actual use is closer to 75-80%. The difference results from variance in use, how long was it in, how long did intercourse last, was intercourse repeated without re-using gel? An individual woman's anatomy may play a factor. A tilted uterus may hide the cervix from the chemical barrier of the gel.