Implanon implants are effective as a contraceptive for up to three years. During this period, the implant continuously releases a low dose of the hormone etonogestrel to assist with preventing pregnancy. After three years, the hormone levels decrease, making it less effective. 

At this stage, the implant should be removed or replaced to ensure continued contraceptive protection. The removal and replacement procedures are straightforward and can be done during the same appointment if desired.

Irregular bleeding is a common side effect of Implanon, especially in the first few months. To manage this, your doctor may prescribe medications such as nonsteroidal anti-inflammatory drugs (NSAIDs) or hormonal treatments like the combined oral contraceptive pill to regulate bleeding. In some cases, the bleeding improves over time without additional treatment.

 If bleeding remains heavy or bothersome, discussing alternative contraceptive options with your doctor is advisable.

Implanon contains the active ingredient etonogestrel, a synthetic form of the naturally occurring hormone progesterone. The implant is a small, flexible plastic rod, which is inserted under the skin of the upper arm. The hormone is released steadily over time, providing continuous contraception. Etonogestrel works primarily by preventing ovulation, thickening cervical mucus, and thinning the uterine lining.

Some users of Implanon report weight gain, although studies have shown that this is not a universal side effect. Weight changes can result from a variety of factors, including lifestyle changes, diet, and individual reactions to the hormone. 

If you are concerned about weight gain while using Implanon, it's important to discuss this with your doctor, who can help you understand the potential causes and provide guidance on managing your weight.

Implanon is more than 99% effective in preventing pregnancy, making it one of the most reliable forms of contraception available. However, no contraceptive method is completely foolproof. 

The chance of becoming pregnant with Implanon is extremely low, but if you experience symptoms of pregnancy, such as a missed period or nausea, it's important to take a pregnancy test and consult your doctor.

Implanon begins to work immediately if it is inserted within the first five days of your menstrual cycle. If it is inserted at any other time in your cycle, it may take up to seven days to become effective. During this time, you should use an additional method of contraception, such as condoms, to ensure you are fully protected against pregnancy.

Implanon does not cause infertility. Once the implant is removed, your fertility should return to normal relatively quickly, usually within a few weeks. Many women are able to conceive shortly after removal, and there is no evidence to suggest that long-term use of Implanon has any negative impact on fertility.