Dear korn18,

The shot (brand name Depo-Provera) is one of the most effective forms of birth control — it's up to 99.7 percent effective when used correctly.

Irregular bleeding is a common side effect of the shot. While some women have heavier, longer periods, most women who experience a change in bleeding find that their periods become fewer and lighter, and often, they stop altogether.

Getting a period each month can be reassuring to a woman who doesn't wish to be pregnant. A woman who misses periods because she is on the shot might worry about pregnancy, but it is very unlikely that a woman would become pregnant while on the shot.

Being on the shot would not affect the accuracy of a pregnancy test. Pregnancy tests work by detecting a hormone called the human chorionic gonadotropin hormone (HCG). HCG is the hormone that supports pregnancy and starts being released when the fertilized egg implants itself and pregnancy begins.

For more information about the shot, check out Is the Shot Right for Me?

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.