What is the recommended approach for removing an intrauterine device (IUD) that is due for removal in a female patient of reproductive age when the IUD strings cannot be felt?

Management of IUD with Missing Strings

When an IUD is due for removal but strings cannot be felt, first perform a transvaginal ultrasound to confirm the IUD location—if the device is properly positioned in the uterine cavity and the patient is not pregnant, the IUD can safely remain in place and continue providing contraception. 1

Initial Assessment Algorithm

Step 1: Rule Out Pregnancy

• Perform a pregnancy test immediately, as management differs entirely if the patient is pregnant 1
• If pregnant, attempt removal as soon as possible to reduce risks of spontaneous abortion, septic abortion, preterm delivery, and infection 1

Step 2: Transvaginal Ultrasound

• Obtain transvaginal ultrasound to locate the IUD within the uterine cavity 1
• This is the CDC-recommended first-line imaging modality for missing strings 1

Management Based on Ultrasound Findings

If IUD is Properly Positioned in Uterine Cavity:

• The device can remain in place and will continue to provide effective contraception 1
• No immediate removal is necessary unless the patient desires removal or has concerning symptoms 1
• Counsel the patient to return promptly for heavy bleeding, cramping, pain, abnormal vaginal discharge, or fever 1
• This approach is supported by CDC guidelines and avoids unnecessary invasive procedures 1

If IUD is Not Visualized in Uterine Cavity:

• Obtain an abdominal X-ray to rule out uterine perforation 1, 2
• The X-ray is relatively cheap, non-invasive, and can easily identify an IUD that has perforated through the uterus 2
• If perforation is confirmed, the IUD should be removed as soon as possible, typically requiring laparoscopic removal 1, 2

If IUD is Malpositioned (Low-Lying or in Cervix):

• Remove the IUD without requiring updated imaging if the patient has persistent pelvic pain 3
• CDC guidelines recommend removal of malpositioned IUDs as soon as possible when strings are visible or can be safely retrieved 3

Removal Techniques When Strings Are Not Visible

If Removal is Indicated:

1. Gentle probing of the uterine cavity may identify the IUD and allow retrieval 4
2. Ultrasound-guided removal using alligator forceps is the next step if simple probing fails 4, 5, 6
3. Hysteroscopic-guided removal is superior when ultrasound-guided removal fails, with low complication rates and no major complications reported in case series 6

Critical Pitfalls to Avoid

• Do not assume expulsion when ultrasound shows an empty uterine cavity—always obtain an abdominal X-ray to rule out perforation, especially if the patient has abdominal pain 2
• Do not perform unnecessary interventions when the IUD is properly positioned and the patient is not pregnant—the device can safely remain in place 1
• In pregnancy, do not delay removal attempts as the risks of complications are substantial if the IUD remains in situ 1, 5
• Avoid attributing symptoms to psychosocial causes without ruling out perforation with imaging, as perforated IUDs can cause chronic abdominal pain 2