Depo-Provera is a popularly used birth control method, possibly because of it's advantages and accuracy. There are also many downfalls though.
Depo prevents pregnancy by stopping ovulation. That way there is no egg for sperm to fertilize. Your body naturally builds a uterine lining to prepare for pregnancy, and then releases it when not pregnant (a period). There is generally no lining, or very little when on Depo. So, no lining or egg to be released.
The biggest known advantage is it's 99.7% accurate at preventing pregnancy. According to Wikipedia, there is no worry of detection or forgetting it because it is injected every three months. Usually after the second shot; no periods occur, and there is minimal drug interactions. This shot also decreases the risk of many things including: endometrial cancer by 80%, PID, functional ovarian cysts, uterine fibrosis, ovulation pain, iron deficiency anemia, and seizures.
One OCHS student on Depo found that they developed iron deficiency anemia, but did help with that student's seizures. Another advantage is that dosage doesn't need adjustment for body weight.
The most know disadvantages are weight gain, and osteoporotic effects. Another OCHS student said "I hate it; with the first shot I lost 30 pounds, and the second shot I gained 46 pounds." Other disadvantages are irregular menstrual bleeding, and no STD protection. It increases the risk for breast and cervical cancer, especially in smokers. Depending on when you get the shot, it can take up to 14 days to take effect. Once you decide to get off Depo, there is a delayed return of fertility. Generally by 18 months, fertility is back to normal. Infants born to women exposed to Depo during pregnancy have an 80% greater chance of dyeing within the first year of life, again according to Wikipedia.
