There are three types of contraceptive injections in the UK: Depo-Provera, which lasts for 13 weeks, Sayana Press, which lasts for 13 weeks, and Noristerat, which lasts for eight weeks. The most popular is Depo-Provera. Noristerat is usually used for only short periods of time – for example, if your partner is waiting for a vasectomy.
The contraceptive injections Depo-Provera and Noristerat are usually given into a muscle in your bottom, although sometimes may be given in a muscle in your upper arm. Sayana Press is given under the skin (subcutaneously) rather than into a muscle, in the abdomen or thigh and can be injected yourself. This way you can be given up to 1 years supply to go home with and inject yourself, saving you appointments. For more information about the self-injectable Sayana Press, please visit Sayana's website.
The contraceptive injection contains progestogen. This thickens the mucus in the cervix, stopping sperm reaching an egg. It also thins the womb lining and, in some, prevents the release of an egg.
9,12 or 13 weeks
- Works for up to 13 weeks (depending on type used)
- You don’t have to prepare for or interrupt sex
- You don’t have to remember to take a pill every day
- Not affected by other medicines
- May provide some protection against cancer of the womb and pelvic inflammatory disease
- Suitable for women who can’t take oestrogen
- May help with premenstrual symptoms
- May reduce heavy or painful periods, and in some women periods stop altogether
- Fertility returns to normal after the injection wears off although this may take up to 12 months
- The injection is safe to use while you are breastfeeding.
- Weight gain, headaches, mood swings, breast tenderness and irregular bleeding are possible short-term side effects.
- Periods may become more irregular or longer, or stop altogether. By the end of the first year of injection use, 70% of women are having no bleeding at all.
- Using Depo-Provera affects your natural oestrogen levels, which can cause thinning of the bones if used for an extended time.
- There can be a delay of up to 1 year before the return of your periods and fertility once stopping the injection. Irregular bleeding may continue for some months after you stop the injections.
- Allergic reaction to the injection is possible but rare.
- Risk of a small infection at the site of the contraceptive injection is rare.
- Does not protect you against STIs
How effective is it?
If the injection is always used perfectly, according to instructions, it’s over 99% effective. This means that fewer than one injection user in 100 will get pregnant in one year.
If the injection is not always used according to instructions, about 6 in 100 injection users will get pregnant in one year.
It’s important to have your next injection at the right time. If you miss, or are late, having the next injection you may no longer be protected from pregnancy.
What makes it less effective?
- Some prescribed and complementary medicines
- Follow-up injections must be given on time.
For more information visit the FPA website.