Contraceptive injection is a long-acting progestin, injected intramuscularly in the local to play the effect of contraception, the main side effects of contraceptive injection are: 1, local skin reactions, after the injection of local may have skin atrophy, hair loss, pigment loss. 2, weight change, after the injection of contraceptive injection will have an increase in diet, body anabolic increase in weight. 3, after the injection of menstrual changes, irregular bleeding and amenorrhea. 4. Breast enlargement, a large amount of progesterone will cause breast development. At the same time may cause breast lactation, excessive progesterone may cause tumors in the reproductive parts. 5, easy to contraceptive failure, because the validity of intramuscular injection of contraceptive injection is relatively short, if not used continuously may cause the problem of contraceptive failure.