What are the next steps if the strings for an Intrauterine Device (IUD) removal and replacement cannot be located?

Management of Missing IUD Strings

When IUD strings are not visible, an ultrasound examination should be performed immediately to determine the location of the IUD, as it may have been expelled or perforated the uterine wall. 1

Diagnostic Algorithm

1. Initial Assessment:

   • Confirm that strings are truly not visible at the cervical os
   • Rule out pregnancy with a pregnancy test
   • Assess for symptoms such as abdominal pain, abnormal bleeding, or discharge

2. Imaging:

   • First-line: Transvaginal or transabdominal ultrasound to determine if the IUD is:
     • Correctly positioned in the uterus
     • Malpositioned within the uterus
     • Not visualized in the uterus (suggesting expulsion or perforation)

3. If ultrasound cannot locate the IUD:

   • Obtain an abdominal X-ray to determine if the IUD has perforated and migrated into the peritoneal cavity 2
   • This is a relatively inexpensive and non-invasive approach to confirm perforation

Management Based on IUD Location

1. IUD Confirmed in Uterine Cavity (Strings Retracted)

• Office-based removal options:
  • Attempt retrieval using alligator forceps or IUD hook under direct visualization
  • Hysteroscopic-guided removal is highly effective when ultrasound-guided removal fails 3
  • In-office removal of IUDs without visible strings has been shown to be effective, safe, and economically sound 4

2. IUD Not in Uterine Cavity

• If expelled: Offer alternative contraception or replacement IUD
• If perforated:
  • Surgical removal is recommended, with laparoscopy being the preferred method 5
  • Perforation can lead to serious complications including adhesions, bowel obstruction, or damage to surrounding organs

Important Considerations

• The incidence of non-visible strings varies by insertion timing and method:

  • Higher rates of non-visible strings occur with post-placental insertions, particularly after cesarean deliveries (27.6% vs 1.9% for vaginal insertions) 6
  • High fundal placement of the IUD decreases expulsion rates but may increase the likelihood of strings retracting into the uterus 1

• Risk factors for IUD malposition or expulsion:

  • Distorted uterine cavities
  • Uterine fibroids that distort the cavity (11% expulsion rate vs 0-3% without fibroids)
  • Inadequate insertion technique
  • Immediate postpartum insertion 5

Common Pitfalls to Avoid

1. Assuming expulsion without confirmation: Always verify with imaging before concluding the IUD has been expelled
2. Dismissing symptoms: Persistent abdominal pain may indicate perforation, even years after insertion 2
3. Excessive force during removal attempts: This can cause uterine perforation or IUD fragmentation
4. Delayed management: Perforated IUDs should be removed promptly to prevent complications

Remember that hysteroscopic removal has been shown to have no major complications or readmissions when performed by experienced providers 3, making it the preferred approach when office-based attempts fail.