What is the best method to verify Intrauterine Device (IUD) placement?

Best Method to Verify IUD Placement

Clinical evaluation (checking for IUD strings) is the best method for routine verification of IUD placement, with transvaginal ultrasound reserved for situations where strings are not visible, when there are symptoms of malposition (pain or abnormal bleeding), or when cervical dilation was required during insertion. 1

Routine Post-Insertion Verification

String Check as Primary Method

• Clinical evaluation by checking for IUD strings has excellent negative predictive value (0.98-1.0) for confirming proper IUD position 1
• The positive predictive value of clinical string check is 0.60 immediately after insertion and 0.54 at 6-week follow-up, meaning when strings are not palpable, further evaluation is warranted 1
• Patients should be taught to check for strings themselves after each menstrual period 2

When Ultrasound Is NOT Routinely Indicated

• Routine transvaginal ultrasound for all IUD insertions is not indicated because clinical evaluation alone is highly accurate for detecting normal positioning 1
• The prevalence of abnormal IUD position is only 7.7% immediately after insertion and 4.0% at follow-up, making universal ultrasound screening inefficient 1

Selective Use of Ultrasound Verification

Clear Indications for Ultrasound

Ultrasound should be used when:

• IUD strings are not visible or palpable on clinical examination 1
• Patient presents with pelvic pain or abnormal bleeding after IUD insertion 3
• Cervical dilation was required during insertion, as ultrasound guidance has demonstrated reduced pain in these situations 4
• Severe uterine retroflexion or anteflexion was encountered during placement 5

Optimal Ultrasound Technique

• Three-dimensional (3D) transvaginal ultrasound with coronal view reconstruction is superior to 2D ultrasound for visualizing the entire IUD (shaft and both arms simultaneously) 6, 3
• 3D ultrasound enables complete simultaneous imaging of all IUD parts in 95% of cases 6
• The 3D coronal view can detect IUD arms embedded in the myometrium that are missed on standard 2D views 3
• Standard 2D transvaginal ultrasound in longitudinal and transverse planes is acceptable when 3D is unavailable 7

Clinical Significance of Malposition Detection

Symptoms Associated with Malposition

• 75% of patients with abnormally located IUDs present with bleeding or pain, compared to only 34.5% with normally positioned devices 3
• Specifically, 35.7% of malpositioned IUDs cause bleeding and 39.3% cause pain 3
• 95% (20 of 21) of symptomatic patients with embedded IUDs report symptom improvement after device removal 3

Types of Malposition Detectable

• IUD arms embedded in myometrium (most common abnormality, detected in 16.8% of cases) 3
• Incomplete opening of IUD arms 6
• Displacement into cervical canal 6
• IUD shaft not reaching fundal position 7

Practical Algorithm for IUD Position Verification

Immediate post-insertion:

1. Perform clinical string check 1
2. If strings visible and patient asymptomatic → no imaging needed 1
3. If strings not visible OR difficult insertion → perform ultrasound 4, 1

At follow-up (typically 4-6 weeks):

1. Ask about pain or abnormal bleeding 3
2. Perform clinical string check 1
3. If strings present AND patient asymptomatic → no imaging needed 1
4. If strings absent OR patient has pain/bleeding → perform ultrasound with 3D coronal view if available 3

Common Pitfalls to Avoid

• Do not routinely order ultrasound for all IUD insertions as this increases cost without improving outcomes for asymptomatic patients with visible strings 1
• Do not rely solely on 2D ultrasound views when evaluating for malposition in symptomatic patients, as embedded arms may be missed without coronal reconstruction 3
• Do not dismiss patient complaints of pain or bleeding as "normal adjustment" without ultrasound verification, as 75% of malpositioned IUDs cause these symptoms 3
• Recognize that the first month post-insertion has the highest rate of position changes, making follow-up timing important 7