This is a medication that is injected into either a muscle in your arm or buttock.  

The injection steadily releases the hormone progestogen which prevents the release of an egg each month (ovulation), thickens the cervical mucus to make it harder for sperm to pass through into the womb, and thins the lining of the womb. 

Used correctly it is more than 99% effective, you must remember to have this every 13 weeks otherwise you could be at risk of pregnancy. 

You may not be suitable for the injection if you are pregnant, do not want your periods to change, are planning a pregnancy in the next year, have unexplained bleeding, have or have had heart disease or stroke, have liver disease, have or have had breast cancer, are at risk of osteoporosis.

You can have the injection at any time of the cycle provided you are not pregnant.

If you have the injection after day five of your cycle, then you will need to abstain from sex or use condoms for the next seven days as this starts to work.

It can be given after birth if you are not breastfeeding.

It can be given after abortion or miscarriage.

Long lasting, can be used if you cannot have oestrogen containing contraception, it can reduce heavy and painful periods.

In some cases, users may experience the following side effects:

  • lighter, irregular or no periods - this can carry on for some time after the injections stop
  • a delay of up to one year before your cycle returns to normal - you can become pregnant during this time
  • weight gain
  • headaches
  • acne
  • hair loss
  • low sex drive
  • mood swings.