Common questions about medroxyprogesterone contraceptive injections - Brand names: Depo-Provera, Sayana Press

A medroxyprogesterone contraceptive injection works in 3 ways:

• it stops your body from releasing an egg each month (ovulation)
• it thickens the mucus around the neck of the womb (cervix) which makes it difficult for sperm to get through
• it makes the lining of the womb thinner so that a fertilised egg is less likely to implant and be able to develop

When you start having medroxyprogesterone contraceptive injections:

• if you have the injection in the first 5 days from when your period starts it will protect you from pregnancy straight away
• if you have the injection at another time or if you have not been having periods, it will take 7 days to start working – you'll need to use another type of contraception such as condoms for 7 days

If you have medroxyprogesterone contraceptive injections for a long time, your bones may become weaker or fragile (osteoporosis).

To help prevent this, regular exercise can help, and make sure you get enough calcium in your diet to help strengthen your bones. Milk, cheese and leafy greens contain lots of calcium.

The effects of the injection will reduce 13 weeks after your last injection, so you could get pregnant. Your periods should return to normal after a few months.

Your fertility should return after you stop having medroxyprogesterone contraceptive injections, but how long this takes varies from a few months to over a year.

You may lose weight when having medroxyprogesterone contraceptive injections, but it's more common to gain weight.

Weight gain is often less than 4lbs (2.2kg) over 1 to 2 years, but it can sometimes be up to 8lbs (4.4kg).

Eating a healthy, balanced diet and regular exercise will help you keep to a healthy weight.

Medroxyprogesterone contraceptive injections can affect your periods in different ways.

Your periods may become irregular and, in some cases, heavier. They can also become shorter, lighter, or stop altogether. This can carry on for several months after you stop having the injections.

You may find that it improves your monthly cycle, reducing heavy bleeding and period pain. It can also help with premenstrual symptoms.

There are many different methods of contraception available. Which one is best for you depends on your lifestyle, your general health, and personal preferences.

Medroxyprogesterone contraceptive injections last for several weeks, so they can be useful if you do not want to have to remember to use contraception every day or every time you have sex.

They can also be useful if you cannot take contraception that contains oestrogen, such as the combined pill.

It takes time for your fertility to return after you stop having the injections, so they may not be suitable if you may want to get pregnant in the near future.

They do not protect you against sexually transmitted infections (STIs).

There is a similar contraceptive injection that contains a different type of progestogen called norethisterone (brand name Noristerat).

Find out more about methods of contraception.

Medroxyprogesterone contraceptive injections can make some people feel dizzy or tired. If this happens to you, do not drive, cycle or use tools or machinery until you feel better.

It's an offence to drive a car if your ability to drive safely is affected. It's your responsibility to decide if it's safe to drive. If you're in any doubt, do not drive.

Talk to your doctor or pharmacist if you're unsure whether it's safe for you to drive while having medroxyprogesterone contraceptive injections. GOV.UK has more information on the law on drugs and driving.

Yes, you can drink alcohol while having medroxyprogesterone contraceptive injections.

You can eat and drink normally while having medroxyprogesterone contraceptive injections.