Choosing a method of contraception can be a difficult task for many individuals and couples. There are many ways of preventing pregnancy, each suiting some people more than others.
One method that is available is an injection of a drug known as medroxyprogesterone acetate. When used in a long-acting or 'depot' form - known as Depo-Provera or a generic equivalent, Depo-Ralovera - this provides reliable contraception for 3 months. After that, if contraception is still needed, the injection is repeated.
Depo-Provera and Depo-Ralovera are very similar to the natural female hormone progesterone. They work by stopping the ovaries from releasing an egg (ovum). The release of an egg is known as ovulation and usually happens once a month. With no egg released, pregnancy is impossible.
The greatest benefit of Depo-Provera and Depo-Ralovera is that once the injection has been given, nothing more needs to be done. Other types of contraception may fail for 'human' reasons, such as forgetting to take a pill or failing to put on a condom properly.
The main disadvantage with Depo-Provera and Depo-Ralovera contraception is that, after an injection, it is hard to predict when ovulation will restart and fertility return. Although the injections are repeated every 3 months, it may take as long as 18 months after an injection before pregnancy is possible.
For this reason, Depo-Provera and Depo-Ralovera are not recommended as contraceptives for couples who want short-term protection, such as between having babies.
Another problem with Depo-Provera and Depo-Ralovera is that periods may be unpredictable and irregular. They are usually lighter and disappear completely in about half the women using this method for more than a year. Occasionally, weight gain, headaches, mood changes and reduced libido will happen as side effects of the hormone. Long-term use may have an effect on bone density and this may need to be monitored.
For those who do not wish to become pregnant for quite some time, Depo-Provera and Depo-Ralovera are highly reliable contraceptives.
Last Reviewed: 12 February 2010