Because yes, it can happen. 

Listen, you’re bound to have questions when choosing the best birth control for you: Will I remember to take a pill around the same time every day? Will I want to get pregnant before the IUD expires? Do I trust condoms completely?

These are all valid (and necessary!). But a recent paper published in BMJ Case Reports brings up a new question that you probably haven’t worried about—yet. Can a birth control method end up somewhere in your body it definitely isn’t supposed to be?

Turns out, that can happen—and it did. According to the case report, an unnamed woman, 31, had an Implanon NXT contraceptive implant inserted into her arm. The devices are small, flexible, plastic rods that are inserted under the skin in the upper arm and are used to prevent pregnancy just like birth control pills and IUDs by using hormones to prevent ovulation.

Credit: BMJ

The patient featured in the new case report wasn’t new to Implanon NXT devices—she’d used them for eight years and had three different ones inserted. After the woman’s third implant was inserted, however, she noticed abnormal bleeding that lasted for three months.

When she went to get checked out by her doctor, they couldn’t find the implant in her arm (yikes), so her doctor ordered a chest X-ray—that’s when the doctor discovered the woman’s implant had migrated to her left lung.

So…how could this even happen? Great question. According to the case report, implant devices can move within your body if they’re inserted too deep into your arm. Additionally, “vigorous physical exercise” after the implant is inserted could make it move around in there.

Luckily, the woman featured in the report healed well after having the implant removed from her lung. There were no complications with her surgery, and she was discharged after four days in the hospital.

But if you have an Implanon NXT (or are considering one), don’t panic. To quote the case report itself: “Migration of an Implanon to the lung is very rare, with few cases described in the literature.” Phew!

However, if you notice your periods are irregular well after insertion, it’s important to see your doctor. The chances of your device moving around in your body are small, but it can’t hurt to double check if you think something’s off.