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Contraceptive injection
Effectiveness:
Over 99 per cent effective. Less than one woman in 100 will get pregnant in a year.
How it works:
Releases the hormone progestogen which stops ovulation, thickens cervical mucus to prevent sperm reaching an egg, and thins the lining of the uterus (womb) to prevent a fertilised egg implanting.
Advantages:
• Lasts for 12 weeks (Depo-Provera) or eight weeks (Noristerat).
• May protect against cancer of the uterus, and offers some protection from pelvic inflammatory disease.
• You don’t have to think about contraception for as long as the injection lasts.
• Not affected by other medicines.
Disadvantages:
• Periods may stop, be irregular or longer.
• Periods and fertility may take time to return after stopping the injection.
• Some women gain weight.
• Some women report having headaches, acne, mood changes and breast tenderness.
• The injection cannot be removed from the body so any side-effects may continue for as long as it works and for some time afterwards.
Contraceptive patch
Effectiveness:
Over 99 per cent effective if used according to instructions. Less than one woman in 100 will get pregnant in a year.
How it works:
A small patch stuck on the skin releases two hormones, estrogen and progestogen. This stops ovulation, thickens cervical mucus to prevent sperm reaching an egg, and thins the lining of the uterus to prevent a fertilised egg implanting.
Advantages:
• You don’t have to think about it every day.
• It is not affected if you vomit or have diarrhoea.
• Can make bleeds regular, lighter and less painful.
• May protect against cancer of the ovary, colon and uterus.
• When you stop using the patch your fertility will return to normal.
Disadvantages:
• Not suitable for overweight women or smokers over 35 years old.
• Very low risk but serious side-effects may include blood clots (thrombosis), breast cancer and cervical cancer.
• Can be temporary side-effects such as headaches, nausea, mood changes and breast tenderness.
• Possible skin reaction.
Comments:
• May be seen.
• New patch has to be used each week for three weeks out of four.
• Some medicines can make it less effective.
• Less effective in women who weigh 90kg (14 stone) or over.
• Breakthrough bleeding and spotting common in the first few months.
Implant
Effectiveness:
Over 99 per cent effective. Less than one woman in 1,000 will get pregnant over three years.
How it works:
Small flexible rod put under the skin of the upper arm. Releases the hormone progestogen. It stops ovulation, thickens cervical mucus to prevent sperm reaching an egg, and thins the lining of the uterus to prevent a fertilised egg implanting.
Advantages:
• Works for three years but can be taken out sooner.
• You don’t have to think about contraception for as long as the implant is in place.
• When the implant is removed your fertility will return to normal.
Disadvantages:
• Periods are often irregular, much longer or stop.
• Acne may occur.
• Some women report having mood changes and breast tenderness.
• It requires a small procedure to fit and remove it.
Comments:
• Put in using a local anaesthetic and no stitches are needed. Tenderness, bruising and some swelling may occur.
• You may feel the implant with your fingers, but it can’t be seen.
• Some medicines may stop the implant from working.
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