Nexplanon is one of the most effective birth control methods available, but no method is absolutely perfect. The honest answer is that pregnancy with Nexplanon is extremely rare, occurring in fewer than 1 out of 100 users over a year of typical use. When pregnancy does happen, it is almost always linked to a specific error — most commonly the implant being inserted too late in the menstrual cycle or the device not being placed correctly.
How Does Nexplanon Actually Prevent Pregnancy?
Nexplanon is a tiny, flexible rod about the size of a matchstick. A clinician inserts it just under the skin of your upper arm. It releases a steady dose of the hormone etonogestrel, a progestin, into your bloodstream.
This hormone works in three distinct ways. First, it stops ovulation in most cycles. Without an egg released, pregnancy cannot occur. Second, it thickens the cervical mucus, making it harder for sperm to swim through. Third, it thins the lining of the uterus, though this is not the primary mechanism of action.
These combined effects make the implant highly effective. The failure rate is less than 1 percent, which is comparable to sterilization procedures like tubal ligation.
Can You Get Pregnant From Nexplanon? Facts on the Failure Rate
Yes, pregnancy from Nexplanon is possible, but the statistical risk is very low. Clinical trials and large observational studies consistently report failure rates below 1 percent. This means for every 100 women using the implant for a year, fewer than one will become pregnant.
This places Nexplanon in the top tier of contraceptive effectiveness. It outperforms birth control pills, patches, and vaginal rings, which have typical-use failure rates around 7 to 9 percent. The difference comes down to user error. Pills require daily attention. Once the implant is in place, it works continuously for up to five years.
Most reported pregnancies occur because of a timing issue at insertion. If the implant is placed later than day 5 of the menstrual cycle, ovulation may have already started. In this situation, pregnancy is possible in the first week after insertion unless a back-up method is used.
Why Do Nexplanon Pregnancies Happen?
When a pregnancy occurs with Nexplanon, the cause is usually one of three things.
The first is incorrect insertion timing. Clinicians recommend insertion within the first five days of the menstrual cycle. If insertion happens later, the body may be close to ovulation. The implant needs about seven days to reach effective hormone levels. During this window, a back-up method like condoms is recommended if insertion happened after day 5.
The second cause is improper placement. The implant must sit just under the skin. If it is inserted too deep, into muscle tissue, hormone release may be altered. This is why you should feel for the rod after insertion. If you cannot feel it, tell your clinician immediately.
The third cause is drug interactions. Certain medications can speed up how quickly the liver breaks down hormones. These include some seizure medications, St. John’s Wort, and certain HIV treatments. If you take any of these, the implant may be less effective. Your clinician can advise whether an alternative method is better for you.
What Happens if You Get Pregnant on Nexplanon?
If you become pregnant while using Nexplanon, you need medical care right away. There is an increased risk of ectopic pregnancy — a pregnancy that implants outside the uterus, most commonly in the fallopian tube. This is a medical emergency.
An ectopic pregnancy cannot continue and requires treatment. Symptoms include sharp pelvic pain, vaginal bleeding, and shoulder tip pain. If you have these symptoms, seek emergency care immediately.
If the pregnancy is inside the uterus, the implant should be removed. The progestin in Nexplanon has not been proven to cause birth defects, but the safety data is limited. Most clinicians recommend removal once pregnancy is confirmed to reduce any potential risk.
It is also important to understand that a pregnancy on Nexplanon is not caused by the implant itself failing in most cases. It is usually the result of a timing or placement issue. This distinction matters because it affects how you and your clinician respond.
How to Confirm the Implant Is Working
You should be able to feel your Nexplanon implant. Run your fingers along the inside of your upper arm. The rod should be firm and easy to locate. If you cannot feel it, this does not automatically mean it is broken, but it does mean you need an ultrasound to confirm placement.
If the implant is not in the correct position, it may not release hormones effectively. In this case, you are not fully protected against pregnancy. Use a back-up method and contact your clinician for imaging.
Routine checks are not required. Once placement is confirmed, the implant works continuously. You do not need to check it daily or monthly. Feeling for it occasionally is sufficient.
What to Do if You Miss a Period on Nexplanon
Missing a period on Nexplanon is normal. Many users have irregular bleeding or no bleeding at all. This is a common and expected side effect of progestin-only contraception. It does not indicate pregnancy.
However, if you have no bleeding for several months and then develop new symptoms like breast tenderness, nausea, or unusual fatigue, take a pregnancy test. Home urine tests are reliable. If the test is positive, contact your clinician for a blood test and ultrasound.
Do not wait for a missed period to take a test if you have other symptoms. Nexplanon changes your cycle so much that relying on bleeding patterns is not a useful indicator of pregnancy.
Can Nexplanon Cause Infertility Later?
No. Nexplanon does not cause permanent infertility. Once the implant is removed, hormone levels drop quickly. Ovulation typically resumes within the first month. Most women return to their normal fertility within a few cycles.
This is a common concern, but the evidence is clear. The implant only suppresses ovulation while it is in place. It does not damage the ovaries or eggs. Fertility after removal is the same as it would have been without the implant.
If you are planning a pregnancy, you can schedule removal and begin trying right away. There is no required waiting period.
Nexplanon vs. Other Birth Control Methods
Choosing a birth control method depends on your priorities. Nexplanon offers high effectiveness without daily effort. It is also reversible. The table below compares it to other common methods.
| Method | Typical Use Failure Rate | How Often You Act | Reversible |
|---|---|---|---|
| Nexplanon | Less than 1% | Once every 5 years | Yes |
| IUD (hormonal) | Less than 1% | Once every 3-7 years | Yes |
| Birth control pill | About 7-9% | Daily | Yes |
| Condom | About 13-18% | Every act of sex | Yes |
| Tubal ligation | Less than 1% | Permanent | No |
These failure rates come from large population studies. They reflect real-world use, not perfect use. Nexplanon’s advantage is that real-world use and perfect use are nearly identical because there is no daily action required.
Signs of a Problem With the Implant
Most Nexplanon users have no problems. But you should know the warning signs that require medical attention.
Pain, redness, or swelling at the insertion site that worsens after a few days may indicate infection. This is uncommon but treatable. If the implant feels bent or broken, it is likely damaged and may not work properly. You would need a replacement.
If you experience severe lower abdominal pain, especially on one side, seek medical care. This could indicate an ectopic pregnancy. While rare, the risk is higher in Nexplanon users who become pregnant compared to the general population.
Heavy or prolonged bleeding is not dangerous in most cases, but it can lead to anemia if it continues. Your clinician can offer treatments to regulate bleeding while the implant stays in place.
Frequently Asked Questions
Can you get pregnant while on Nexplanon?
Yes, but it is extremely rare, with a failure rate of less than 1 percent per year. Most pregnancies happen due to insertion timing errors or improper placement.
How soon after Nexplanon insertion are you protected?
You are protected immediately if the implant is inserted within the first five days of your menstrual cycle. If inserted later, use a back-up method like condoms for seven days.
What are the signs of pregnancy on Nexplanon?
Signs include breast tenderness, nausea, fatigue, and a positive home pregnancy test. Because Nexplanon often stops periods, a missed period alone is not a reliable sign.
Does Nexplanon cause weight gain?
Some users report weight gain, but clinical studies show mixed results. Weight changes are not guaranteed and vary from person to person.
Nexplanon is a safe, highly effective birth control option for most people. The risk of pregnancy is very low, and the risk of serious complications is even lower. If you have concerns about your implant, placement, or side effects, talk to your clinician. They can confirm the device is working and address any symptoms you are experiencing.
