Contraceptive Injection

Sexual and Reproductive Health

What is a contraceptive injection?
The contraceptive injection releases the hormone progestogen steadily into your bloodstream. It lasts for 8 or 13 weeks, depending on which injection you have.

How does the contraceptive injection work?
The contraceptive injection releases the hormone progestogen in your bloodstream. This prevents pregnancy by:

  • Thickening the cervical mucus, which makes it difficult for sperm to move through the cervix and reach the egg
  • Making the lining of your uterus thinner so it is less likely for a fertilised egg to implant itself
  • Inhibiting ovulation


How many contraceptive injections are available?
There are three injections available:

  • Depo-Provera - lasts for 13 weeks
  • Sayana Press - lasts for 13 weeks
  • Noristerat - lasts for 8 weeks

Your medical practitioner will guide you on which contraceptive injection is best for you.

How effective is the contraceptive injection?
The injection is 99% effective if it is taken at the right time. If you miss it, or are late, when having the next injection you may no longer be protected against pregnancy. With typical use, it is around 94% effective, meaning that around 6 in 100 injection users will get pregnant in a year.

When does it start to work?
You can have the injection at any time during your menstrual cycle if you are not pregnant. Your medical practitioner will guide you as to whether extra contraception is needed. Usually this depends on the day of the injection and your menstrual cycle.

How is a contraceptive injection given?

  • Depo-Provera - injected deep in muscle, usually in your buttocks/arm
  • Sayana Press - injected deep in muscle, usually in your buttocks
  • Noristerat - injected beneath the skin at the front of the thigh or abdomen


What are the advantages of the contraceptive injection?

  • You do not have to think about contraception for either 8 or 13 weeks
  • It is not affected by other medicines
  • It does not interrupt sex
  • You do not have to remember to take a pill every day
  • It may reduce heavy periods and help with premenstrual symptoms for some people
  • You can use it if you are breastfeeding
  • It is an option if you cannot use oestrogen-based contraception e.g. combined pill, contraceptive patch, and contraceptive vaginal ring


What are the disadvantages of the contraceptive injection?

  • Your periods may change and become irregular, heavier, shorter, lighter or stop. This may continue for some months after you stop the injections
  • It does not protect you against STIs
  • You may experience weight gain
  • The injection cannot be removed from your body, so even if you have side-effects, you must be prepared to continue during this time
  • You may experience side effects like headaches, acne, hair loss, decreased sex drive and mood swings
  • Delay in period of up to 1 year before your fertility returns


Can I get pregnant after I stop taking the contraceptive injection?
You may experience a delay of up to 1 year before your fertility returns after you stop taking the injection.

What are the risks of the contraceptive injection?
Your medical practitioner will discuss all risks and benefits with you. The following are the risks of the contraceptive injection:

  • Osteoporosis
  • Allergic reaction to the injection
  • Reaction to the injected site - irritation or scar
  • Research indicates that people who use hormonal contraception may have a small increased risk of breast cancer


How does it affect my bones?
Depo-Provera or Saraya Press affect the natural oestrogen levels and may cause thinning of the bones. Bones tend to replace themselves when you stop the injection. Thinning of the bones may be a problem for those who are at risk of osteoporosis. Your medical history should be discussed with your medical practitioner for advice and guidance.

Who can use a contraceptive injection?
Most women can have a contraceptive injection. However, it may not be suitable for you if:

  • You think you might be pregnant
  • You do not want change in your periods
  • You want to have a baby next year
  • If you have or had in the past:
    • Breast cancer
    • Unexplained vaginal bleeding
    • Arterial diseases or history of heart disease or stroke
    • Liver disease
    • Risk of osteoporosis


Can I bleed when I start the contraceptive injection?

  • Your period may change
  • Most of the time periods will stop completely
  • Others will have irregular periods or spotting (bleeding between periods)
  • Some will have periods that last longer or heavier

If you are uncomfortable with any of these, speak to your medical practitioner and discuss other methods of contraception or other possible causes in case of uncontrolled bleeding.

Can I switch to another method of contraception?
The injection cannot be removed from your body, so its effects will persist during the time it is effective for. If you wish to change the type of contraception, seek medical advice and guidance. As soon as you stop taking the injection, additional contraceptive methods such as condoms are required.

Can I have a contraceptive injection after a miscarriage?
You can have the contraceptive injection immediately after a miscarriage. If you have the injection more than 5 days after the miscarriage, additional contraception (condoms) is recommended.

I have just had a baby. When can I have a contraceptive injection?
The contraceptive injection can be started after birth. If you start the injection later than 21 days, you will need addition contraception such as condoms for the next 7 days.

How often should I go for a check-up?

  • Ask for advice from your healthcare provider when you are due for a next appointment
  • If you are experiencing any problems since you started having the injection, or have any concerns, speak to your healthcare professional.


If I have the contraceptive injection, am I protected from Sexually Transmitted Infections?
No, only male and female condoms (when used correctly and consistently) protect you from STIs.