Getting pregnant on Nexplanon is extremely rare, but it can happen. With a real-world failure rate of about 0.02 pregnancies per 100 women per year, the implant is the most effective reversible contraceptive available. Still, a small number of pregnancies do occur, and if you’re one of those cases, there are specific things you need to know about how it happens, how to recognize it, and what it means for the pregnancy.
How Rare Pregnancy on Nexplanon Actually Is
In the largest real-world tracking study of Nexplanon users (the NORA study), only 3 pregnancies occurred while the implant was actively in place out of thousands of participants. That translates to a Pearl Index of 0.02, meaning roughly 2 out of every 10,000 women using the implant for a year became pregnant. For context, the birth control pill has a typical-use failure rate closer to 7 out of 100.
The FDA recently extended Nexplanon’s approved duration from 3 years to 5 years, with clinical trial data showing zero pregnancies during years 4 and 5. So the implant doesn’t lose effectiveness as it ages within its approved window.
Why It Sometimes Fails
When pregnancy does occur on Nexplanon, there’s usually an identifiable reason. The most common culprits fall into three categories.
Drug interactions. Certain medications speed up how your liver breaks down the hormone in Nexplanon, lowering its levels in your blood. The biggest offenders are some seizure medications (like carbamazepine, phenytoin, and topiramate), the antibiotic rifampicin (used for tuberculosis), and the herbal supplement St. John’s wort. Several HIV and hepatitis C medications can also reduce the implant’s effectiveness. If you take any of these, your provider should discuss backup contraception or alternative methods.
Insertion problems. According to prescribing data reported by healthcare professionals, about 12.6 out of every 1,000 insertions involve some kind of error, whether a partial insertion, a placement that’s too deep, or in very rare cases, a complete failure to insert the implant at all. Deep insertions (where the rod ends up closer to muscle or connective tissue than intended) account for most of these issues. After insertion, you should be able to feel the rod just under the skin of your inner upper arm. If you can’t feel it, let your provider know.
Timing of insertion. If the implant isn’t placed during the recommended window (typically the first 5 days of your period, or with specific timing when switching from another method), it may not be effective right away. In those cases, you need a backup method like condoms for 7 days. If you had unprotected sex before the implant had time to work, pregnancy is possible.
Why Pregnancy Can Be Hard to Recognize
One of the trickiest aspects of getting pregnant on Nexplanon is that the implant’s normal side effects closely mimic early pregnancy symptoms. Nexplanon commonly causes missed periods (up to and including no period at all), nausea, sore breasts, back or stomach pain, and weight gain. Those are also classic signs of early pregnancy.
If your period has already stopped or become irregular on the implant, you lose the most obvious signal that something has changed. This means pregnancies on Nexplanon can go undetected longer than they otherwise would. If you notice new or intensifying symptoms that feel different from your usual experience on the implant, a home pregnancy test is a reasonable step. The implant does not interfere with the accuracy of pregnancy tests.
What It Means for the Pregnancy
In the NORA study, researchers tracked the outcomes of all pregnancies that occurred in participants, including those that happened while the implant was in place, shortly after removal, or before insertion. Of 26 total pregnancies across all timing categories, 22 resulted in the birth of a healthy child. One ended in a spontaneous miscarriage, two were elective abortions, and one was an ectopic pregnancy.
The hormone in Nexplanon (a type of progestin) has not been shown to cause birth defects. If you discover you’re pregnant with the implant in place, the standard step is to have it removed. Continued exposure isn’t known to harm fetal development, but since the implant is no longer serving its purpose, there’s no reason to leave it in. Removal is quick and can be done at any point during a regular office visit.
Ectopic Pregnancy: A Small but Real Risk
An ectopic pregnancy is one that implants outside the uterus, most often in a fallopian tube. While the overall risk of any pregnancy on Nexplanon is vanishingly small, when a pregnancy does occur on a progestin-only method, the chance that it’s ectopic is somewhat higher than with a natural conception. In the NORA study, one of the pregnancies tracked was ectopic.
Ectopic pregnancies are a medical emergency if they progress. Warning signs include sharp or stabbing pain on one side of the lower abdomen, vaginal bleeding that’s different from your usual pattern, dizziness, or shoulder pain. These symptoms warrant prompt medical evaluation regardless of what contraception you’re using.
What to Do if You Suspect Pregnancy
Take a standard home pregnancy test. These detect a hormone (hCG) that your body only produces during pregnancy, and Nexplanon does not affect the result. If the test is positive, schedule an appointment with your provider to confirm the pregnancy with bloodwork or ultrasound and to have the implant removed.
If the test is negative but your symptoms persist or feel unusual, test again in a week. Very early pregnancies can produce hCG levels too low for a home test to pick up.
You’ll have the same range of options as anyone else with an early pregnancy: continuing the pregnancy, adoption, or abortion. The presence of the implant doesn’t change what’s available to you or add medical complications beyond the need for a simple removal procedure. The choice is entirely yours, and your provider should support whatever decision you make without pressure in either direction.