Q: I've heard from friends about birth-control shots. Can you tell me what they are, and is it OK for a 15-year-old to get them?
A: What you are referring to is a new form of birth control that has recently been approved by the Food and Drug
Administration. This form of birth control contains a chemical (depot medroxyprogesterone acetate or DMPA) very similar to the female hormone progesterone.
It is manufactured in a liquid form that is injected into the muscle. The hormone is then very slowly absorbed into the bloodstream and provides protection against pregnancy for approximately 12 weeks. We think that DMPA works by preventing your body from producing an egg each month although it may also work by making it more difficult for an egg to be fertilized.
Birth control shots are an extremely effective method of pregnancy prevention with fewer than 1 percent of women who use this method for a year getting pregnant. You must remember, however, to get the shot every 12 weeks. What is also important to remember is that the shots do not offer any protection against AIDS or other sexually transmitted diseases. Therefore, you must also use condoms for protection.
There are some other side effects you should be aware of. Many women find that their periods become irregular and last longer and that they spot frequently. Over time, irregular periods become less of a problem, and in fact after a year of using this method, more than half of women stop having periods altogether. Other side effects may include weight gain (about 3 to 5 pounds in the first year), headaches, breast tenderness and fatigue. The shots may also slightly reduce the density of your bones, but most people feel this is not a serious problem. Research studies are continuing.
Is this method right for you? Certainly, it is medically OK for you at 15 to get birth control shots if you don't have any health problems. Before you decide, you should schedule an appointment with your health-care provider to discuss the benefits and risks of this method. Many teen-agers find it helpful to discuss these issues with their mothers.
In the end, though, only you can decide if the effectiveness of the DMPA shots outweighs any potential problems from using them. Don't be afraid to go to your doctor or a family planning clinic to find out more.
Dr. Wilson is director of general pediatrics at Johns Hopkins Children's Center; Dr. Joffe is director of adolescent medicine.