Depo-provera is an injectable progesterone which is a highly effective form of contraception.
If you opt for this method, you will receive a dose of progesterone as an injection. The hormone is similar to the progesterone that is released by your ovaries during the second half of your menstrual cycle. It is 99.7% effective making it one of the most reliable methods of contraception. For effective contraception it MUST be given every 12 weeks. If you are more than five days late for your next injection you will need to use extra precautions for 2 weeks from the day of the injection.
It acts in three ways
Reasons for not using Depo-Provera
- By preventing your egg cells from ripening and being released from the ovary. You cannot become pregnant, as there is no egg to be fertilised by your partnerís sperm.
- It also causes changes in the lining of the womb to make pregnancy less likely
- It thickens the mucus at the entrance to the womb so that it is more difficult for sperm to enter the womb.
Common side effects
- If you have had cancer of the breast, ovary, or womb.
- If you have unusual vaginal bleeding for which the reason is unknown
- If you could be pregnant
- If you have significant risk factors for osteoporosis, this method of contraception should not be considered until other options have been explored.
- Irregular periods. Depo-Provera usually disturbs the pattern of your periods. After the first injection, you might get irregular, sometimes prolonged bleeding, or spotting. 30% of women have no periods at all (amenorrhoea) after the first injection. This is nothing to worry about; in fact some women find it a welcome side effect! If you suffer very heavy or prolonged bleeding, please discuss with the nurse. It can be helped by giving the next injection earlier.
- After 4 injections of Depo-Provera, most women lose their periods completely but might get the occasional bleed, which can be lengthy. It is quite usual for this to happen and need not concern you, although it might be inconvenient. Please discuss with the nurse if the bleeding is very heavy or prolonged.
Your periods should return to normal within a few months of stopping the injections.
- Weight gain. You might put on weight. 60% of women in the clinical trials gained about 5lbs in the first year of use. You might continue to gain weight after the first year. The weight gain is probably due to the hormone increasing your appetite, so you could try to limit what you eat and this might help prevent weight gain.
- Delay in return of fertility. Depo-Provera can cause a delay in the return of fertility following the last injection. This is not permanent and in most women, the effect will have worn off in 5-6 months. Over 80% of women will conceive within a year of the last injection. There is no evidence that Depo-Provera has a permanent effect on fertility.
- Reduction in bone density. Some women who use Depo Provera may lose significant bone mineral density. This effect may be more important in adolescents and so it's use should be carefully considered in women under 18 years. Use for more than 2 years need to be carefully evaluated in women of all ages. This is new information available from December 2004.
This article published on
25 November 2005
Next review date 11/1/2013
Contraception and pregnancy