This page gives you some information about injectable contraception, also known as the jab. Only on type is available in Ireland, it is called Depo-Provera. This is an injection that releases the hormone progestogen into your body. It can be used by women who cannot use other methods of hormonal contraception. One injection gives 12 weeks protection. It works like the pill but last for between 8 -12 weeks.

How effective is the injection?

Injectable contraception is over 99% effective. This means that less than 1 in every 100 women who use the injection will get pregnant each year if the injection is given regularly.

How Is It Used?

The hormone is injected into a muscle, usually during the first 5 days of a period, and is released very slowly into the body. Further injections are needed every 12 weeks. Discuss with you doctor the best time to have you first injection. It you have just had a baby it is believed that delaying the injection for 6 weeks often makes irregular bleeding less likely. It does not effect you milk supply. A small amount of hormone enters the milk, but is thought to be harmless for the baby.

How Does It Work?

While similar in many ways to the hormone in the progestogen-only pill, injectable hormone stops the body releasing an egg each month.


  • Particularly useful for those who find it hard to remember to take a pill every day
  • May reduce heavy periods.
  • Can make period pain or pre-menstrual tension less likely
  • The injection is not affected by vomiting or diarrhoea, or certain medication
  • Injections offer some protection against womb cancer
  • Depo-Provera injection lasts 3 months


  • Injections don’t protect against sexually transmitted infections
  • Injections must be given by a doctor or a nurse
  • You have to remember to have the injections on time every 3 months
  • Your periods can become irregular or stop
  • You might have bleeding between periods
  • Fertility and periods can be slow to return when you stop getting the injections
  • Can lead to some weight gain.
  • Can cause slight thinning of the bones by reducing bone mineral density (usually recovers once the injections stop).

Who can use the injection?

The contraceptive injection is suitable for most women. A doctor or nurse will ask about your own and your immediate family’s medical history, weigh you and take your blood pressure, just to check it will be suitable for you.

Women who are under 18 years old may be able to use the contraceptive injection, but only after careful examination by a doctor because of its effect on bone density.