Depo-Provera (medroxyprogesterone acetate) is a form of birth control. It is an injection, or shot, that contains progestin. This is a natural hormone that your ovaries produce each month as part of your menstrual cycle. You must get it from your primary care or women’s doctor. They give you the injection in either your upper arm or buttock. It can go into a muscle (intramuscular) or under your skin (subcutaneous).
Depo-Provera prevents pregnancy by stopping ovulation (the release of an egg by your ovaries). It thickens your cervical mucus, which makes it hard for sperm to reach and fertilize an egg. It also thins your uterine lining, which makes it hard for a fertilized egg to implant, or attach, to your uterus.
Depo-Provera works for about 3 months at a time. To prevent pregnancy, you have to get 1 shot from your doctor 4 times a year, about 12 to 14 weeks apart. If you get it in the first 7 days of your cycle, it works right away. If you don’t, you’ll need to use another form of birth control for 1 week. Your doctor will confirm you are not pregnant before giving you the injection.
Most women who use Depo-Provera have changes in their menstrual periods. These may include:
• bleeding or spotting between menstrual periods
• an increase or decrease in menstrual bleeding
• no menstrual bleeding at all.
About half of women who use Depo-Provera stop having periods after 1 year. This is not harmful. Menstrual bleeding usually returns to normal when you stop using Depo-Provera. It may take about 9 to 10 months to get pregnant after your last shot.