Getting pregnant on Nexplanon is extremely rare, but it’s not impossible, and the implant’s own side effects can make it genuinely hard to tell the difference. With a failure rate of roughly 0.02 pregnancies per 100 women per year of use, the implant is the most effective reversible contraceptive available. Still, if something feels off, your instinct to check is reasonable.
Why Nexplanon Makes Pregnancy Hard to Detect
The core problem is overlap. Nexplanon works by releasing a steady dose of a progestin hormone that suppresses ovulation, thickens cervical mucus, and changes the uterine lining. Those same hormonal effects produce side effects that look a lot like early pregnancy. Nausea, breast tenderness, and skipped periods are all listed among the implant’s common side effects by the Mayo Clinic. They’re also the textbook first signs of pregnancy.
The biggest source of confusion is missed periods. Many people on Nexplanon stop getting a period entirely, a condition called amenorrhea. When you’re already used to not bleeding, you lose the single most reliable early signal that something has changed. This is normal and expected with the implant, but it removes the alarm bell most people rely on.
Signs That Suggest Pregnancy, Not Side Effects
If you’ve been on Nexplanon for a while and your body has settled into a pattern, pay attention to new symptoms that break that pattern. The implant’s side effects typically show up in the first several months and then stabilize. A sudden wave of nausea, new breast soreness, or unexpected fatigue after you’ve been on the implant for a year or more is worth investigating.
Symptoms that lean more toward pregnancy than side effects include:
- New or worsening nausea, especially in the morning or triggered by smells, after months of feeling fine on the implant
- Breast changes beyond tenderness, such as darkening of the area around the nipple or visible vein patterns
- Unusual fatigue that feels different from your baseline
- Frequent urination without a urinary tract infection
- Light spotting or cramping that doesn’t match your usual pattern on the implant
None of these on their own confirm pregnancy. But if you’re experiencing several at once, especially after a long stretch of feeling normal on the implant, a pregnancy test is the straightforward next step.
When a Home Pregnancy Test Works
A standard urine pregnancy test is just as accurate for someone on Nexplanon as for anyone else. The hormones in the implant do not interfere with the hormone that pregnancy tests detect (hCG). If you’re worried, you can take one at any time. For the most reliable result, test with your first urine of the morning, when hCG concentration is highest.
If your test is negative but symptoms persist, wait a week and test again. Very early pregnancies can produce hCG levels too low to detect on the first try. A blood test at a clinic can pick up lower levels of hCG sooner if you want a definitive answer without waiting.
Situations That Raise the Risk
While the implant’s overall failure rate is extraordinarily low, certain situations can reduce its effectiveness or signal that something isn’t right.
You can’t feel the implant. The rod should be palpable just under the skin of your inner upper arm. If you press gently and can’t locate it, the implant may have migrated deeper into tissue or, in rare cases, was never properly placed. A non-palpable implant should be evaluated with imaging. If the rod isn’t where it should be, you may not be fully protected.
You’re past the five-year mark. The FDA now approves Nexplanon for up to five years of use, extended from the original three-year recommendation. A clinical trial found zero pregnancies in years four and five. However, once you pass five years without replacement, effectiveness is no longer guaranteed.
Certain medications. Some drugs that affect how your liver processes hormones can lower the implant’s effectiveness. These include certain seizure medications and some treatments for tuberculosis or HIV. If you’ve started a new medication and aren’t sure whether it interacts, that’s worth confirming with a pharmacist or provider.
Body weight. There has been some concern that higher body weight could reduce the implant’s hormone levels over time, though clinical data hasn’t demonstrated a clear increase in pregnancies. It remains one of the most effective options regardless of weight, but some providers discuss it as a theoretical consideration.
What Happens If You Are Pregnant on Nexplanon
If a pregnancy test comes back positive, the implant needs to be removed. The progestin it releases is not associated with birth defects, but the rod serves no purpose once pregnancy has occurred and should come out promptly.
One thing to be aware of: although ectopic pregnancy (where a fertilized egg implants outside the uterus, usually in a fallopian tube) is extremely rare with Nexplanon, the absolute incidence amounts to roughly 0.002 per 100 implants. If you get a positive test and experience sharp or one-sided pelvic pain, shoulder pain, or dizziness, seek medical attention quickly. Ectopic pregnancies require immediate treatment.
A Simple Routine for Peace of Mind
Because the implant removes your most obvious monthly signal, building in a periodic check can save you weeks of anxiety. Some people take a home pregnancy test once a month or every few months as a habit, the same way you’d check your smoke detector batteries. Tests are inexpensive and available at dollar stores, and their accuracy doesn’t depend on what birth control you use.
You can also make a habit of feeling for the implant in your arm every few weeks. It should feel like a thin, matchstick-sized rod just beneath the surface. If it’s there and you’re within the five-year window, the odds are overwhelmingly in your favor. The NORA study, one of the largest real-world studies of the implant, tracked over 10,000 women and found only three pregnancies during active use.