Depends on regular injection every 12 weeks.
Over 99% effective.
Less than one woman in 100 will get pregnant a year.
How it works
An injection into the buttocks slowly releases the hormone progesterone into the body over 12 weeks.
It stops the woman from releasing eggs, i.e. it stops ovulation.
Possible Side Effects
- increased weight
- irregular bleeding
- no periods
- fertility may not return for a year or more after stopping the injection
- breast tenderness / acne / bloating / headaches / mood swings
Advantages / Benefits
- reliable if injections are on time.
- no period pain
- usually no heavy periods
- some protection against pelvic inflammatory disease
- may protect against cancer of the womb
- no action required between injections
- not suitable for women over 45
- not suitable for young teenagers
- not suitable if injections are not acceptable
- not suitable for smokers over 40
- not suitable for anyone with a history of breast cancer
Who can provide it?
GP or Sexual Health Service
Any unwanted effects will remain for 12 weeks.
Users should under go a bone mineral density scan after five years use, if they have had no periods.
Must be on time for injections.