Contraceptive implant: how it works, placement, side effects
Last updated September 3, 2026.
The contraceptive implant is a small, flexible tube placed under the skin of your upper arm - it releases a progestin (etonogestrel) that prevents ovulation. You may know it as Nexplanon. The most set-and-forget option: years of protection from one placement.
What does it treat?
Pregnancy prevention - by stopping the ovaries from releasing eggs. No protection against HIV or other sexually transmitted infections.
How is it used?
A healthcare provider places it under the skin of the inner upper arm in a quick office procedure - a pregnancy test may come first, and the provider picks the timing. It can be replaced after 5 years if you want to continue, and removed at any time if you want to stop or switch - fertility returns quickly after removal. After placement, you should be able to feel the rod under the skin: check for it, and if you cannot feel it, use backup protection and call your provider.
Side effects to know
- Common: changes in menstrual bleeding patterns - the most common effect, from lighter to irregular to none; headache; acne; breast tenderness or pain; vaginal swelling, redness, irritation, burning, or itching; weight gain; and sleep trouble, weakness, low energy, fatigue, or mood change.
- Serious - call your doctor immediately or get emergency care: the implant becoming lost, broken, or bent; the clot set - shortness of breath, leg pain, sudden chest pain, sudden severe headache, sudden vision changes, weakness or numbness in an arm or leg, trouble speaking; lower abdominal pain or swelling; a breast lump; yellowing of skin or eyes; and unusual bleeding, including unusually heavy menstrual bleeding or bleeding lasting more than 7 days in a row.
Who should not get it?
Flag history of blood clots, stroke, heart attack, liver disease or liver tumors, breast cancer - current or past - and unexplained vaginal bleeding. Etonogestrel may increase the chance of liver tumors or breast cancer: the risk conversation with your doctor is part of choosing it.
When is it an emergency?
Sudden chest pain, trouble breathing, face drooping or speech trouble, or sudden vision loss is a 911 call. For other urgent concerns, Poison Control is 1-800-222-1222. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper.
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Common questions
How well does it work, and for how long?
It is among the most effective methods available - placed once, it prevents ovulation continuously, and MedlinePlus notes it can be replaced after 5 years if you want to continue. No daily, weekly, or monthly action to forget: the effectiveness does not depend on you remembering anything. Removal is any time you choose, and fertility returns quickly after.
What will it do to my periods?
Expect change: irregular bleeding or spotting is the most common effect in the first months, and over time many land on lighter periods or none at all - all normal patterns for this method. The call-your-doctor versions: bleeding that is unusually heavy, or bleeding that runs more than 7 days in a row. The first 3 to 6 months are the settling window - judge the pattern after it.
What is the check-for-the-rod habit?
After placement you should be able to feel the thin rod under the skin of your inner upper arm - a monthly finger check confirms it is where it should be. If you cannot feel it, or it feels bent or broken: use backup contraception and call your provider promptly - a displaced implant needs to be found, and pregnancy protection is uncertain until it is.
What is the placement appointment like?
A quick office procedure: the skin of the inner upper arm is numbed, the rod slides in through a small applicator, and a bandage covers it - minutes, with soreness and bruising for a few days after. A pregnancy test may come first, and timing is chosen around your cycle or current method so protection is continuous. Removal is similar - small numbed opening, rod out.
Why did my provider ask about clots and breast cancer?
The screening list is the safety gate: history of blood clots, stroke, heart attack, liver disease or liver tumors, breast cancer, or unexplained vaginal bleeding can rule the implant out or reshape the choice - and etonogestrel may increase the chance of liver tumors or breast cancer, per the medication guide. The risk conversation is part of the method, not a formality before it.
Does it protect against infections?
No - pregnancy prevention only, not HIV or other sexually transmitted infections. Condoms remain the protection for that front, and the two combine well: the implant handles the pregnancy risk in the background while condoms handle the infection risk per encounter.