Can you explain what depo-shot is?

Birth control: Depoprovera is a hormone injection given once every three months. It is an extremely effective form of birth control. It protects against fibroids, endometriosis, ovarian and uterine cancer. It can cause a weakening of your bones so you must have adequate calcium intake. 90% of all women who use it will stop getting their periods on it. Irregular bleeding during the first 6 months is common.