Depo works by: 

• preventing ovulation (egg release from the ovaries)
• thickening the mucus of the cervix so that the sperm can not enter the uterus (womb). 

It may take up to 7 days to start working. If you are late having the injection, the effectiveness of Depo in preventing pregnancy is reduced.

Starting Depo for the first time requires an assessment by a doctor and getting a prescription (script). 

Assessments and scripts can be obtained from Family Planning Tasmania clinics or your doctor.

Family Planning Tasmania also has a clinic stock of Depo (so no need to go to the chemist with your script).

You may not be able to have a Depo injection if you have: 

• liver disease
• difficulty with intramuscular injections
• cardiovascular disease
• plans to become pregnant within 6-12 months
• diabetes
• difficulty in tolerating changes in your periods
• depression

Depo is not suitable if you have: 

• an allergy to Depo
• breast cancer and some other forms of cancer
• low bone density

• Between 96-99.8% effective
• Cheap and long acting (up to 12 weeks)
• Most users will have no periods or very light bleeding during their periods
• Period pain and discomfort may be reduced
• Can be used while breastfeeding
• An alternative for those who cannot have the hormone oestrogen

• If you are late getting your injection, it may not work
• It is impossible to reverse the effects of an injection once it is given
• If side effects occur, they may last up to three months
• There could be a delay in return to fertility. On average, the delay is about nine months from the last Depo injection.

• Periods can stop completely in 50% to 60% of users
• Irregular or spot bleeding
• Prolonged bleeding, which usually improves with time 
• Heavy bleeding
• Headaches
• Skin changes
• Bloating
• Tender breasts
• Mood changes
• Around 20% of users will gain some weight

There are medications that may help with prolonged or heavy bleeding. Contact a Family Planning Tasmania Clinic to make an appointment if this is an issue for you.

• At your assessment the doctor will assess your suitability for Depo
• A pregnancy test is usually carried out during the initial assessment
• The first injection is usually given during the first five days of your menstrual period. This is to ensure that you are not pregnant
• In some cases, it is necessary to use condoms for seven days after the injection
• Your doctor will review your risks for loss of bone density while you are using Depo 
• Follow-up injections are given every 12 weeks to continue protection against pregnancy. To renew your prescription, you will need to be reviewed by a doctor every six months
• Depo does not protect you against sexually transmitted infections (STIs) or blood borne viruses