Understanding Contraceptive Implants
Birth control implants like Implanon and Nexplanon are a form of long-acting reversible contraception (LARC). They consist of a small, flexible rod, roughly the size of a matchstick, that a healthcare provider inserts just under the skin of the upper arm. Once inserted, the rod continuously releases a synthetic progestin hormone called etonogestrel.
This hormone prevents pregnancy in several ways, primarily by inhibiting ovulation, which is the release of an egg from the ovary. It also thickens the cervical mucus to block sperm from reaching the egg and thins the uterine lining to prevent a fertilized egg from implanting. Both Implanon and Nexplanon offer highly effective, three-year protection against pregnancy with a failure rate of less than 1%.
The Evolution from Implanon to Nexplanon
Implanon was first approved by the FDA in 2006, offering an innovative single-rod system for contraception. However, it was associated with some difficulties, particularly concerning incorrect or deep insertions. These errors could make the implant difficult to locate and remove, potentially leading to complications and reduced effectiveness. In response to these issues, the manufacturer developed and released Nexplanon in 2010, effectively replacing the older device. Implanon is no longer manufactured or commercially available in the U.S. and many other parts of the world.
Radiopacity: A Crucial Safety Upgrade
One of the most significant improvements in Nexplanon is its radiopacity. The Nexplanon rod contains a small amount of barium sulfate, a substance that makes it visible on X-rays, CT scans, and other imaging techniques. This feature is a crucial safety advancement that directly addresses a major limitation of the original Implanon.
Key benefits of Nexplanon's radiopacity:
- Confirmation of Insertion: After placement, a healthcare provider can use an X-ray to confirm that the rod was inserted correctly and is in the proper position.
- Easier Localization for Removal: If the implant cannot be felt by touch (palpation) during removal, imaging can be used to pinpoint its exact location. This helps prevent prolonged or complex removal procedures.
Improved Insertion Applicator
The second major improvement in Nexplanon is its enhanced, pre-loaded applicator. The new applicator is designed to be easier and more accurate for healthcare providers to use, reducing the risk of insertion errors. While Implanon was also inserted using an applicator, the improved design of the Nexplanon version provides better control and minimizes the chance of placing the implant too deeply. This change ensures the implant remains in the subdermal tissue layer, where it is intended to be. The updated insertion mechanism also makes the procedure quicker and more straightforward.
Comparison of Implanon and Nexplanon
To highlight the specific differences, here is a direct comparison of the key features of Implanon and Nexplanon.
| Feature | Implanon | Nexplanon |
|---|---|---|
| Availability | Discontinued and no longer available in the U.S. or other key markets. | Currently available and is the standard single-rod implant. |
| Hormone | Contains 68 mg of etonogestrel. | Contains 68 mg of etonogestrel (same hormone). |
| Radiopacity | Not radiopaque (not visible on X-ray). | Radiopaque (visible on X-ray and other imaging). |
| Insertion Device | Older applicator design, which was more prone to insertion errors, particularly deep placement. | Improved, pre-loaded applicator for easier and more accurate shallow insertion. |
| Primary Purpose | Contraception for up to 3 years. | Contraception for up to 3 years. |
| Side Effects | Similar side effect profile to Nexplanon (irregular bleeding, headaches, weight gain). | Similar side effect profile to Implanon (irregular bleeding, headaches, weight gain). |
Efficacy and Side Effects
Despite the changes to the device itself, the overall effectiveness and side effects of Nexplanon are largely comparable to Implanon, as they use the same hormone. Both implants boast a very low failure rate, making them one of the most effective birth control methods available. Some studies have suggested a slightly lower failure rate for Nexplanon, likely due to the reduced risk of insertion error.
The most common side effect for users of both implants is a change in menstrual bleeding patterns, which can include irregular bleeding, spotting, heavier periods, or no periods at all. Other potential side effects are similar and include headaches, weight changes, mood swings, and acne. It is important for anyone considering Nexplanon to discuss their medical history with a healthcare provider to ensure it is a safe option.
The Bottom Line
Ultimately, the comparison between Implanon and Nexplanon is a story of product evolution driven by safety and patient experience. While the core contraceptive function remains the same, Nexplanon's introduction represents a crucial step forward in improving the safety and reliability of the hormonal implant. The addition of radiopacity and a superior insertion device directly addresses the main shortcomings of its predecessor. The discontinuation of Implanon ensures that patients now receive the safer, updated version. While the user experience in terms of effectiveness and side effects is very similar, Nexplanon is unequivocally the better option from a medical and procedural standpoint, thanks to its enhanced safety features.
For more information on the Nexplanon implant and its use, review the official FDA documentation.
