Birth control: sponge

What it is: A disposable foam sponge containing spermicide.
How it works: Absorbs and kills sperm.
Effectiveness: Between 84 and 91% if you haven’t given birth, and between 68 and 80% if you have. It should be used with another form of contraception.
Convenience: Can be inserted several hours before sex.
Best for: Women who want backup for a condom.
Side effects: May increase the risk of vaginal infection.
Price tag: About $5.
Good to know: The sponge is effective for 12 hours, so can be left in place if you’re planning a lengthy tryst.

Our experts:
Dara Maker, family physician at Women’s College Hospital in Toronto
Roey Malleson, clinical associate professor of family practice at University of British Columbia
Ronald Weiss, assistant professor of medicine at University of Ottawa