Contraceptive implants and injections

Disadvantages of contraceptive implants and injections

Contraceptive implant

Disrupted periods

Periods may change significantly in the first year of using Implanon. They will usually become irregular and may become very heavy, shorter and lighter, or stop altogether.

This may settle down after the first year, but occasionally continues as long as the implant is fitted.

Other side effects

Some women report the following:

  • headaches,
  • acne,
  • nausea, and
  • breast tenderness.

These usually stop after the first few months. If you have prolonged or severe headaches or other side effects, see your doctor.

Infection

In rare cases, the area of skin where the implant has been fitted can become infected. If this happens, the area will be cleaned and may be treated with antibiotics.

Contraceptive injections

It can take up to 12 weeks for injected progestogen to leave the body. If you have any side effects, they may continue during this time and for some time afterwards.

Disrupted menstrual cycle

Periods may change significantly in the first year of using contraceptive injections. They will usually become irregular and may be very heavy, shorter and lighter, or stop altogether. This may settle down after the first year, but occasionally continues as long as the injected progestogen remains in the body.

It can take a while for your periods and natural fertility to return after you stop using the injection. It takes around eight to 12 weeks for injected progestogen to leave the body, but you may have to wait longer for your menstrual cycle to return to normal if you are trying to get pregnant.

Until you are ovulating regularly each month, it can be hard to work out when you are most fertile for conception. In some cases, it can take three months to a year for your periods to return to normal.

Weight gain

You may put on weight when you use contraceptive injections, although some women lose weight. Use of the injections may be associated with an increase in weight of up to 2-3kg over one year.

Bone risk

Using contraceptive injections can cause thinning of the bones but does not increase your risk of bone fracture. Your bone replaces itself when you stop the injection, so it does not appear to cause any long-term problems.

Other side effects

Some women report the following:

  • headaches,
  • acne,
  • tender breasts, and
  • changes in mood and/or sex drive.
Last updated: 04 October 2011

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