Depo Provera

Depo Provera is a hormone used for contraception. It is given by injection and its effects will last for three months at a time.

It is similar to progesterone, which is one of the two main hormones made by a woman's ovaries during her normal cycle.

How does Depo Provera work?

When a woman has Depo Provera, her body senses the presence of the hormone so that her own hormone production is ‘switched off’. Because of this, her ovaries will not release an egg and this is how pregnancy is prevented. This is very similar to how the Pill works. Depo Provera is also sometimes used in the treatment of endometriosis.

How well does it work?

Depo Provera is a highly effective method of contraception when it is given every three months (99.8 per cent effective).  About one in twenty (six per cent) of women will still get pregnant when using Depo Provera; this is very low compared with other methods.

Side effects

During a normal menstrual cycle, your hormones cause the lining of your uterus to thicken in preparation for a pregnancy. If you don’t get pregnant, the lining of your uterus breaks away and you bleed – this is your period.

When you have Depo Provera, your hormone levels are low and stable throughout your cycle, so the lining of your uterus doesn’t thicken as it normally would.  When it comes time for your period there is very little lining to shed and so you bleed less than you normally would.

After two to three injections, many women will have no periods at all because there is no lining building at all. Some women will have nuisance bleeding, which is usually light and irregular. Occasionally a woman will have troublesome heavy bleeding, which can usually be controlled by hormone treatment.

Other effects

• A small amount of weight gain sometimes occurs, although many women have no change and some lose weight.
• Some women may be troubled by headaches, abdominal discomfort and mood changes.
• Some women have a reduced interest in sex, particularly women who are prone to depression.
• A small minority of women experience other side effects, which may be a nuisance but are unlikely to be serious. These include allergic reactions, fluid retention and breast soreness.

Advantages

• Depo Provera is highly effective with a very low failure rate.
• For many women the loss of periods is an advantage with relief of symptoms such as premenstrual tension and period pain.
• Depo Provera is also likely to cause some reduction in risk of ovarian cancer, endometrial (uterine) cancer, endometriosis and possibly pelvic infection.
• An injection is given every 12 weeks and no other effort or remembering is required.

Disadvantages

• Some women do not wish to see their doctor every three months for an injection.
• Some women experience side effects as already described, which may be uncomfortable or unpleasant.
• Once the injection has been given, the hormone cannot be removed. If a woman wants to stop the Depo Provera she has to wait for it to wear off. In some women, periods can be slow to return after the injections are stopped – sometimes  6 to 12 months. However, more than half will fall pregnant within 12 months and over 90 percent within two years.

Other things to think about

Hormone levels are very low while using Depo Provera, so there is some concern that this may lead to thinning of the bones (osteoporosis) in women who use Depo Provera for a long period of time. The importance of this is not yet known, but the changes would be expected to happen more slowly than those that occur normally after menopause and reverse after the injections stop.

Although it is extremely difficult to prove a complete lack of risk, Depo Provera has not been shown to have any effect on the risk of breast cancer. It should be noted that protective effects against cancer of the ovary and uterine lining are very likely. No ill effects on the developing baby have been shown to occur if Depo Provera is given when a woman is already pregnant or in the very rare case where a woman becomes pregnant despite the injection.

Who can use Depo Provera?

Depo Provera can be used by most women who do not have any serious medical problems and by many women who use other forms of contraception. It may also be suitable for women who cannot take the combined pill for medical reasons.

Who should not use Depo Provera?

Depo Provera is not suitable for women who are experiencing the following:

• bleeding disorders or taking anticoagulant medication
• undiagnosed abnormal bleeding
• history of some forms of cancer
• certain other serious medical problems
• already pregnant
• wanting to become pregnant within 12 months.

Where to get more information

• Your local doctor (GP)
• Women's Welcome Centre (Victoria only)
  Tel: (03) 8345 3037 or 1800 442 007 (rural callers)

Information about long acting reversible contraception (LARC), including contraceptive injections, is also available in Arabic, Chinese, Hindi, Spanish, Urdu and Vietnamese – see Related Health Topics below

---

---