How does the contraceptive injection work?

The contraceptive injection contains one hormone of the progestogen class that blocks ovulation, and therefore prevents you from getting pregnant. Each dose contains enough hormones to protect you for 13 weeks. The contraceptive injection does not protect against sexually transmitted infections (STIs).

 

Since the contraceptive injection does not contain oestrogen-type hormones, it can be used by women who cannot use such hormones.