An injection given by a GP or nurse, which prevents pregnancy by releasing the hormone progestogen into a bloodstream. The most commonly-used jab is Depo-Provera, which lasts for thirteen weeks. Occasionally Noristerat is used, which lasts for 8 weeks. A newer, self-injectable type called Sayana Press lasts for 13 weeks however isn't widely available.
The hormone progestogen stops the ovaries from making eggs and thickens the mucus in the cervix, forming a plug in the neck of the womb, which makes it hard for sperm to pass through and fertilise an egg. The womb also becomes thinner, which means if an egg were to fertilise, it couldn't attach itself to the womb.
Convenience. One jab lasts for 8-13 weeks so you don?t have to think about contraception during that time. It?s good for women who can?t use the hormone oestrogen, which is found in the pill, contraceptive patch and vaginal ring. It?s 99% effective and may help reduce heavy periods and menstrual pain.
Possible side effects include headache, stomach pain, weight gain, acne, irregular bleeding between periods, vaginal discharge, changes in your mood and sex drive and thinning of the bones. It can?t be removed if you decide you would like to try for a baby and it may affect your fertility and ability to conceive for up to a year after you stop taking it. It doesn?t protect against sexually transmitted infections (STIs) so to have safe sex, you will still need to use condoms.
Most women but if you have, or have had, breast cancer, a stroke, heart or liver disease, unexplained vaginal bleeding or you are at risk of osteoporosis (bone thinning), the injection may not be suitable so seek medical advice first. You can have the injection three or six weeks after giving birth, depending on whether you are breastfeeding or not, and straight after a miscarriage or a termination.
Last updated August 1, 2018