Abstract: The progestogen-releasing subdermal implants were popular contraceptive methods for those reproductive age women because of their effectiveness，long-duration and safety. The implants were suitable for most women with the improved releasing system and optimized progestogen. Unscheduled bleeding was the most common adverse event while other adverse events rarely occured. All adverse events will gradually alleviate, without any serious adverse events. It is disadvantage that implants must be inserted and removed by a surgical professional. Resent studies concentrated on the safety and adverse events of implants, including their influences on metabolism, bone mineral density, breast milk and infants, etc. At present, two main problems are how to reduce adverse events and to develop new biodegradable implants.

Key words: Contraceptive agents, Progestins, Embedding therapy, Validation studies