The Basics of Nexplanon

The birth control implant (Nexplanon) is a 4 cm rod that steadily secretes progestin to prevent pregnancy. Nexplanon is inserted underneath the skin of the arm in the doctor’s office. It’s FDA approved for 3 years but there is good evidence to support off-label use for up to 4 years, and a couple small studies that even demonstrate efficacy for 5 years. It’s the most effective form of long-acting reversible contraception on the market at 99.95%.

I always describe implants and IUDs as a love or hate relationship. There’s very little in between. For the implant, around 80% (some studies show a little higher) of people continue it beyond a year and about 20% of people have it removed within the first year. That 20% hate it and tend to have really bothersome side effects, most commonly being persistent or frequent bleeding. Most common side effects are irregular bleeding, headache, vaginitis, weight increase, acne, and breast tenderness.

  • 6.5% report mood changes and 5.5% reported depression.
  • It does not affect long-term fertility.
  • People typically have quick return to normal periods and ovulation once removed.
  • The insertion process is really easy and after the poke & burn of lidocaine to numb it up – painless.

Does Nexplanon cause weight gain?

Weight gain is one of the most common questions I get about any hormonal birth control method. For the implant, which only contains progestin, in the clinical trial 13.5% of people reported weight gain during the time period of the trial. This number is just the reporting number meaning, it is the amount of people who gained weight during this time period whether it was related to the implant or not. 2.3% of people removed the implant during the first year specifically because of weight gain suggesting that although some people gained weight, sometimes it wasn’t bothersome.

When it comes to hormonal birth control, we know some people can be more sensitive to the estrogen component and some people can be more sensitive to the progestin component. For people who are more sensitive to progestins, they may have more progestin related side effects: bloating, fatigue, headache, weight gain.

And for a few, the weight gain can be significant. I’ve definitely seen it and have removed a small handful of implants due to the patient being concerned about the weight gain. However, we have to remember that this is still the minority, around 2.3%.

Average weight gain tends to be just above the 1-2 pound average per year that people gain in general with age. There will always be people above average and below average, which can be hard to predict.

The Insertion Device

I know it looks intimidating, but don’t worry, we numb up the arm site with local anesthetic. A little lidocaine can make it completely numb. The lidocaine burns at first when it’s injected but after that, you shouldn’t feel a thing. The device itself is very simple to use and makes it easy to get a correct placement just below the surface of the skin.

The most common complications are local site issues: bruising, redness, swelling, infection, pain, hematoma. Rarely, it can be placed incorrectly. Usually this means inserted too deep making it harder to remove later. In really rare cases, this may require surgery to remove. The are a few case reports out there of it migrating into blood vessels and causing nerve damage, however, this is a handful of reports over millions inserted.

Misplacement or difficulty with insertion happened in 2.6% (in a study of 7,364 insertions):

  • Non-insertion (inserter device failure) 1 case, 0.01%
  • Partial insertion 27 cases, 0.37%
  • Too deep insertion happened in 65 cases or 0.9%
  • Of these 65 cases:
    • 1 injury to nerve or blood vessels (0.01%)
    • 2 located within the muscle (0.03%)
    • 56 located below/in the fascia (0.76%)
    • 6 were not palpable (0.08%)

There are a handful of rare case reports of implants migrating to other places after insertion but this is also out of tens of millions of insertions.

The Most Common Side Effect

The most common side effect is an alteration of bleeding pattern. 

  • 22% will be lucky and have no bleeding, also called amenorrhea. 
  • 33% will have less bleeding than they did before but this could still be irregular and unpredictable. 
  • 24% will have a worse bleeding pattern and roughly half of this group will have it removed because the bleeding was overly bothersome (too frequent or too heavy).

Unlike progestin IUDs, that usually show improvement in bleeding patterns over time, the implant does not. By the 3rd month, that’s usually the pattern that will continue. There are a few things we can try to stop persistent bleeding. Sometimes these things help long term and sometimes they only help while taking them. Bottom line: If you have heavy periods to begin with, this may not be the most reliable way to improve that pattern.

Removal Process

Removal is usually fairly straightforward but occasionally it can also be complicated. And yes, again, we inject local anesthetic to first numb the area. Lidocaine burns going in, but after that you should be numb. People can feel pressure and pushing, but it shouldn’t be overly painful. In the clinical trial, healthcare providers reported difficulties in removal in 1.5% of procedures. (In clinical practice, this may be a bit higher and more variable).

Out of 4,373 removals, 60 (1.5%) difficult removals were reported. Of these:

  • 29 were encased in fibrotic tissue
  • 11 were too deep
  • 6 migrated locally within the arm by no more than a couple cm. (There are rare case reports of implants migrating further or to dangerous places like major blood vessels).
  • 13 required multiple attempts to removal
  • 14 were categorized as “other” issues (bent, broken implants, etc)

Typically, removal shouldn’t take anymore than 2-5 min. Occasionally, implants can be more difficult and can take longer but the vast majority can still be removed in the office. Personally I have encountered only a few truly challenging removals. If you are due to get an implant removed and desire to continue with this method of contraception, a new one can be replaced in the same location.

I have no affiliation with the manufacturer (Merck) and have no disclosures. This post is for education only. 

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