Dear confuse,

It may take up to a year for periods to return after a woman's last shot. Periods become fewer and lighter for most women who get the shot, and often stop altogether. The longer a woman uses the shot, the more likely her periods will stop.

The shot is an injection of a hormone that is similar to progesterone (one of the hormones made by a woman's ovaries to regulate the menstrual cycle). The common brand name of the shot is Depo-Provera — or Depo, for short. When used correctly, the shot is up to 99.7 percent effective against pregnancy.

Hope this information helps!

Take care,

teenwire.com^® Editors

This column is for informational purposes only and is not intended to constitute medical advice, diagnosis, or treatment. If you have a medical problem, please call toll-free 1-800-230-PLAN for an appointment with the Planned Parenthood health center nearest you.