Contraceptive implant migration

Last revised by Arlene Campos on 24 Jul 2023

Contraceptive implant migration is a rare complication of etonogestrel implant insertion. 

  • unable to palpate device in the upper arm
  • chest pain
  • dyspnea
  • non-productive cough
  • menorrhagia
  • irregular vaginal bleeding

Contraceptive implants are most commonly inserted into the medial soft tissues of the upper non-dominant arm. They are 4 cm rod-shaped radio-opaque devices with the most commonly used being Nexplanon (Merck & Co., Inc., USA) and Implanon (Merck & Co., Inc., USA). They inhibit ovulation and are routinely replaced after 3 years. Complications are uncommon with most being local and minor.

However, implant migration is a reported rare complication with approximately 40 recorded (~10 with pulmonary migration) by the USA's Food and Drug administration and 12 published cases (c. 2020) ref

The exact mechanism of migration is unclear but it is theorized that an inadvertent placement of the implant into the venous system may occur during the initial procedure with the implant embolizing via the right heart into the pulmonary arterial system 1

Ultrasound is the first-line modality for locating contraceptive implants. Implants are linear echogenic structures with posterior acoustic shadowing measuring approximately 4 cm in length. 

If unable to locate the device by palpation or ultrasound then a plain film of the shoulder/upper arm is performed. All contraceptive implants are radio-opaque ref. They appear as 4 cm thin rod-shaped structures. If no device is seen then the patient should proceed to a frontal +/- lateral chest radiograph. 

Removal by endovascular procedures has been reported with varying success. The implants tend to endothelialise and become fixed so if left for a long period of time the risk of unsuccessful endovascular removal increases 2-3

The alternative method of removal reported is by thoracotomy and segmentectomy. 

In multiple case reports the device was left in situ with follow up plan including patient review and monitoring of etonogestrel levels. This conservative approach was typically used in the asymptomatic patient who has no desire to conceive with the rationale being that etonogestrel levels may gradually diminish and the device eventually become inactive 4-5

If left in situ there is a risk of further complications including infection, hemoptysis, pneumothorax, chest pain and dyspnea. 

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Cases and figures

  • Case 1
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  • Case 2
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  • Case 3: missing nexplanon
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