A contraceptive injection is a type of birth control that is administered as a shot into the muscle of your arm or buttocks. The injection contains hormones (Progestin) that are released into the bloodstream to prevent pregnancy.
The contraceptive injection works by thickening the cervical mucus, which blocks sperm from reaching the egg, and by preventing ovulation (the release of an egg from the ovary). The injection also causes changes in the endometrial lining, which make it more difficult for a fertilized egg to implant in the uterus.
To use a contraceptive injection, you will receive a shot from a healthcare professional every 12 weeks. The injection provides protection against pregnancy for up to 12 weeks, after which a new shot is needed.
Contraceptive injections are highly effective at preventing pregnancy, and they do not require daily attention like other forms of contraception. However, it is important to remember that contraceptive injections do not protect against STIs, so it is important to use a barrier method, such as a condom, to reduce the risk of STI transmission.
Common side effects of contraceptive injections include:
- Irregular bleeding or spotting
- Weight gain
- Mood changes
- Decreased sex drive
It is important to talk to a healthcare professional about the risks and benefits of a contraceptive injection, and to discuss any health conditions or medications that may affect its use.
Page last reviewed: 6 August 2024