Sexual Health

The contraceptive injection

There are four methods of long-acting reversible contraception (LARC) to choose from; contraceptive injection, the contraceptive implantthe intrauterine device (IUD or non hormonal coil) and the intrauterine system (IUS or hormonal coil). This page is about the contraceptive injection. 

The key thing about long acting reversible contraception methods is that they are all “fit and forget” methods; this means once they are fitted or given, women are protected from pregnancy without having to do or think anything about it, until it needs replacing.
In the UK the contraception injection is Depo-Provera and it lasts for 12 weeks. There is another one called Noristerat that lasts for 8 weeks, but that is rarely used or available now.
“If used correctly, the contraceptive injection is more than 99% effective. This means that less than one woman in 100 who use the injection will become pregnant in a year”- NHS Choices 2015
The injection contains progesterone. This stops ovulation ( the release of an egg every month), thickens the mucus in the cervix (stopping sperm reaching an egg), and thins the womb lining.

One of the main advantages of injections is that women don't have to worry about remembering to take anything, so they are good method for people who are a bit forgetful. It is important to remember that the LARCs do not offer any protection against sexually transmitted infections. If there is any possibility of infection, condoms should be used as well.

There can be many reasons for a woman to choose a LARC method, including concerns about side effects of other methods, wanting to stop using condoms, having trouble remembering to take the pill, concerns about the effectiveness of the pill when sick, irregular painful periods and bleeding or to reduce the risk of pregnancy. People may want to change because they have had problems with other methods.

Some of the women interviewed chose to use injections as their method of contraception after trying the pill or condoms.

Before changing contraception methods there are leaflets to read about what's available or health professionals to talk to at GP surgeries, Family Planning or Brook clinics. Remember, implants and injections do not suit everyone.

Women we spoke to had different experiences of contraceptive injections and, while women often reported being happy with the injection, some stopped taking it because of health concerns. Some used injections as contraception after childbirth. Although one woman thought two weeks after having her baby was too soon for an injection, it is safe to have the injection immediately after giving birth - if not breastfeeding. If breastfeeding, then it is an option six weeks or more after birth.

The majority of women will have less frequent bleeding or none at all when using the contraception injection. A few women get frequent or heavy bleeding especially with the first injections. This usually settles down but if it doesn’t, it is advisable to talk to a doctor or nurse.
We talked to women who had stopped using LARC and started using other methods such as one of the contraceptive pills, and they said that they find it difficult to remember taking it every day. Stefanie has an alarm on her phone to remind her to take her pills and keeps them next to her toothbrush.
We also spoke to women who decided to stop using LARC or had never used LARC. They had a number of reasons for their decision including: experiences of relatives or friends, ‘horror’ stories reported by the media, concerns about LARCs' impact on fertility, possible link between long term use of Depo-Provera and osteoporosis (fragile bones) and also the perception of losing control over their own bodies.

The injection is linked with a small loss of bone density, which usually goes back to normal after stopping the injection. There is no available evidence on the effect of long term injection use on the risk of breaking bones. When considering options, other factors that can reduce the density of bones may be taken into account (such as weight, smoking, other medical conditions, and a family history of osteoporosis).
When injections are stopped, there can be a delay in returning to regular periods and fertility for up to a year. There is no evidence they reduce fertility in the long term.
Women we interviewed commented that the amount of information they got from their GPs regarding LARC was variable and that, often, they were given leaflets to read rather than the time to talk about the different options available to them.

The young women we talked to advised others to get as much information as they could find about long acting reversible contraception and other forms of contraceptives before deciding which one to use. They also reminded people that everyone reacts differently so not to be swayed by the experiences of family members or friends. One of the women we talked to who had used the injection thought that it was better to delay its use until the age of 17 or older and not to use it continuously.

LARCs are over 99% effective against unwanted pregnancies BUT only condoms or not having sex offers protection against sexually transmitted infections, including HIV.

Last reviewed January 2016.

Last updated January 2016.


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