The Short Answer
The birth control implant (brand name: Nexplanon) is a small, flexible rod about the size of a matchstick that is inserted under the skin of your upper arm. It releases progestin steadily for up to 5 years and is the most effective reversible contraceptive available at 99.95%. Once it is in, there is nothing to remember. The main trade-off is irregular bleeding, which affects about 1 in 3 users.
Key Points:
- 99.95% effective - the highest of any reversible method
- Lasts up to 5 years, works from day one
- Inserted and removed in a quick office visit under local anesthesia
- Most common side effect: unpredictable bleeding patterns
- Safe while breastfeeding
How It Works
Nexplanon releases a steady, low dose of etonogestrel (a type of progestin) into the bloodstream. This prevents ovulation (no egg released), thickens cervical mucus (blocks sperm), and thins the uterine lining.
It begins working within 24 hours if inserted during the first 5 days of your period. If inserted at another time, use backup contraception for 7 days.
Insertion
- Takes about 1-2 minutes
- Your provider numbs the inside of your upper arm with a local anesthetic
- The implant is placed just under the skin using a special applicator (similar to getting blood drawn)
- A small bandage covers the site. You may have bruising for 1-2 weeks
- You can feel the implant under your skin - this is normal and how your provider checks that it is in place
What to Expect After Insertion
Week 1: Mild soreness and bruising at the insertion site. Avoid heavy lifting with that arm for a few days.
Months 1-3: Your bleeding pattern will start to shift. This is the adjustment period.
Months 3-6: Your new bleeding pattern usually establishes itself. About 1 in 5 users stop getting periods.
Bleeding Patterns on the Implant
This is the most important section to read before choosing the implant. Bleeding changes are the number one reason people have the implant removed early.
- About 1 in 5 users: No periods (amenorrhea)
- About 1 in 4 users: Infrequent, light bleeding
- About 1 in 4 users: Regular bleeding similar to a natural cycle
- About 1 in 5 users: Frequent or prolonged spotting/bleeding
There is no reliable way to predict which pattern you will have. If your bleeding pattern is bothersome, your provider may prescribe a short course of combined pills or NSAIDs to help regulate it.
Other Side Effects
- Headaches: Common in the first few months, usually temporary
- Mood changes: Some users report mood swings or depressive symptoms. Track your mood to spot patterns.
- Acne: May improve or worsen. Progestin-only methods lack the estrogen that helps clear acne.
- Weight: Small average weight gain reported in studies (2-3 lbs), but this varies widely
- Breast tenderness: Usually temporary
- Ovarian cysts: Functional cysts can form but are typically harmless and resolve without treatment
Who Is the Implant Good For?
- You want the most effective reversible contraception available
- You do not want to think about birth control for years
- You are comfortable with potentially unpredictable bleeding
- You cannot or prefer not to use estrogen
- You are breastfeeding
- You have difficulty remembering daily or weekly medications
Who Might Want to Consider Other Options?
- Unpredictable bleeding would significantly disrupt your life or cause anxiety
- You want to control or eliminate your period (the hormonal IUD is more reliable for this)
- You have a history of depression and are concerned about mood-related side effects
- You strongly prefer a method you can start and stop on your own without a provider visit
Removal
- Takes about 3-5 minutes
- Your provider numbs the area, makes a tiny incision, and pulls the implant out
- A new implant can be inserted through the same incision if you want to continue
- Fertility returns quickly - most people can get pregnant within weeks of removal
Implant vs Other Long-Acting Methods
| Factor | Implant | Hormonal IUD | Copper IUD |
|---|---|---|---|
| Effectiveness | 99.95% | 99.8% | 99.2% |
| Duration | 3-5 years | 3-8 years | 10-12 years |
| Location | Upper arm | Uterus | Uterus |
| Hormones | Progestin (systemic) | Progestin (local) | None |
| Period effect | Unpredictable | Usually lighter | Usually heavier |
| Insertion discomfort | Minimal (arm) | Moderate (cervix) | Moderate (cervix) |
Frequently Asked Questions
Can I feel the implant?
Yes. You can feel it as a small, thin rod under the skin of your inner upper arm. It is not visible and does not restrict movement.
Can the implant move or get lost?
Nexplanon is designed to stay in place. Migration is extremely rare. Your provider will check its position at follow-up visits.
Does the implant affect future fertility?
No. Fertility returns within days to weeks after removal. Studies show no long-term effect on fertility.
Can I exercise and swim with the implant?
Yes. Once the insertion site heals (about a week), you can do all normal activities including swimming, weightlifting, and contact sports.