context: Depo- Provera is a contraceptive method for women that you get as a shot. It's a manmade hormone called medroxyprogesterone, which is similar to progesterone. var s_context; s_context= s_context || {}; s_context['wb.modimp'] = 'vidfloat'; if(webmd.useragent && webmd.useragent.ua.type === 'desktop'){ webmd.ads2.disable Initial Load(); webmd.ads2.disable Ads Init = true; $(function() { webmd.p.pim.increment(); $('.responsive-video-container').insert After('.module-social-share-container'); require(['video2/1/responsive-player/video-loader'], function(video Loader) { video Loader.init({ autoplay: webmd.useragent.ua.type === 'desktop' && ! !s_sensitive, chron ID: $('article embeded_module[type=video][align=top]:eq(0)').attr('chronic_id'), continuous Play: true, cp Options: { flyout: true }, display Ads: true, mode: 'in-article', sticky: true }) }); }); } else { $(function(){ $('.responsive-video-container').remove(); }); } You get the shot in your arm or rear end. It works for up to 12 to 14 weeks. You have to get it every 12 weeks to get its full protection. You might hear people call it a contraception injection or birth control shot. Depo- Provera starts to work as birth control immediately if you get it within the first 5 days of your menstrual period. The Depo- Provera shot is 99% effective in preventing pregnancy. The hormone works on your pituitary gland, causing your ovaries to stop releasing eggs. Without eggs, you can't get pregnant. It also changes the lining of your uterus and the mucus in your cervix. That makes it harder for sperm to reach any eggs that are released. It's OK for most women. But you shouldn't get it if you have: Unexplained vaginal bleeding Liver disease Breast cancer Blood clots Your doctor will be cautious about giving it to you if you're a teenager, or if you have: Diabetes A history of depression A history of heart attack or stroke Osteoporosis or a high risk for it They can include: Irregular menstrual periods, or no periods at all Headaches Nervousness Depression Dizziness Acne Changes in appetite Weight gain Unwanted facial and body hair Hair loss Loss of bone mineral density Belly pain Bloating Breakthrough bleeding Fatigue Less interest in sex Weakness Changes to your menstrual cycle are the most common side effects. You may have irregular bleeding or spotting. After a year of use, about 50% of women will stop getting their periods. If this happens to you, your period should come back when you stop getting the shots. Long-term use of Depo- Provera may lead to loss of bone mineral density, which makes you more likely to get osteoporosis. Your chances are even higher if you've taken the shot for longer than 2 years, especially if osteoporosis runs in your family, you drink a lot, you smoke, or you have other risk factors for the condition. You can become pregnant as soon as 3 to 4 months after your last shot. But it takes some women up to a year or two to conceive after they stop using this type of birth control. This time frame doesn't seem to be linked to how long you got the shots. In addition to preventing pregnancy, this medication has other benefits: You don't have to remember to take it every day or use it before sex. It provides long-term protection as long as you get the shot every 3 months. It's highly effective. You get birth control without having to take estrogen. It may be less expensive than the birth control pills you currently take, depending on your insurance and the type of pill you take. You don't have to interrupt sex to get protection or rely on a risky method like withdrawal. It can make your period lighter and less painful. It might even stop it. It could make you less likely to get endometrial cancer. Regular doctor visits for the shots can be inconvenient. You need to stop taking Depo- Provera several months ahead of time if you plan to become pregnant. It might take up to 10 months to get pregnant after you stop using it. It doesn't protect you against sexually transmitted diseases ( STDs). Use a condom for safer sex.