I've been looking for the answer to "How effective is spermicide once it expires?".
I have a 2 year expired, unopened Options Gynol 2 vaginal contraceptive jelly and called the manufacturer, who told me the only data they had was that they could not guarantee the effectiveness of the product past the expiration date.
I looked at the active ingredient Nonoxynol-9 and could not find information regarding its effectiveness over time.
Looking at the sites at the bottom of this post, many expired drugs are still good far past their expiration date. Factors like storage and open containers may affect deterioration. I would assume that expired contraceptive foam/jelly/film is still effective or somewhat effective past expiration.
I plan to use it along with the pill.
http://www.health.harvard.edu/fhg/updates/update1103a.shtml