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Missing IUD threads — DFSRH MCQ

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ModerateIntrauterine methodsMissing IUD threadsDFSRH

A 29-year-old woman has a copper IUD inserted for contraception. Two weeks later she reports mild cramping and can no longer feel the threads; pregnancy test is negative and speculum examination does not show threads. What is the most appropriate investigation?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: B — Pelvic ultrasound to locate the device

Missing IUD threads require assessment of location, and pelvic ultrasound is the usual first investigation when pregnancy is excluded. Blind attempts can be traumatic and may miss perforation or expulsion. Reassurance without confirming position risks unrecognised expulsion, while CA125 and MRI are not first-line. The pearl is to advise additional precautions until correct intrauterine location is confirmed.

Reference: FSRH Guideline: Intrauterine Contraception