Maybe immediately. If you get the birth control shot within the first seven days after the start of your period, you are protected from pregnancy immediately. If you get the shot within five days after miscarriage or an abortion, or within three weeks after giving birth, you are protected from pregnancy immediately. Otherwise, you need to use some form of backup birth control, like a condom, diaphragm or sponge.
If you have been on Depo-Provera provera (medroxyprogesterone) for longer than a year and you get a period with every other shot are you likely not pregnant?
No. Very unlikely to be pregnant.
I have PCOS have been off Depo-Provera (medroxyprogesterone) shot for a long time same to only way I get. Is to take Provera (medroxyprogesterone) pills when will it be natural again my cycle?
Discuss with doctor. PCOS is a complex set of symptoms involving abnormal hormonal levels resulting in irregular menstrual cycles. Often it also involves Insulin resistance, which can be improved with a healthy diet rich in vegetables and lean protein. In women that are overweight, losing weight will sometimes help improve the menstrual regularity. Birth control pills are often used to regulate the cycle.
How long after the Depo-Provera provera (medroxyprogesterone) shot is given does it become effective?
Few days. It could take a few days to start working, though generally it is considered to work very quickly.
Depends... If you get it right after your period starts, you are protected right away. Any other time, not until after your next period, so you need backup contraception.