A double-blind, triple-arm randomized controlled trial of 1% lidocaine paracervical block for intrauterine device (IUD) insertion

OBJECTIVES: To determine whether a paracervical block (lidocaine 1% with epinephrine 1:100,000 10 mL) decreases pain during intrauterine device (IUD) placement STUDY DESIGN: We conducted a randomized, double-blind trial of three arms: paracervical block, saline injection, or capped needle from June 30, 2022, to August 16, 2024. The primary outcome was the global pain score, rated on a 100 mm visual analog scale. Secondary outcomes included pain perception at procedural timepoints using a numeric score and patient satisfaction. RESULTS: We included a total of 246 patients (n = 82 per group). Overall, participants who received a paracervical block reported lower global pain scores during IUD placement (median 30 mm, interquartile range [IQR] 10-50) compared with those receiving saline injection (median 45 mm, IQR 25-60) or a capped needle (median 45 mm, IQR 20-70) (p = 0.003 and p = 0.001, respectively). Among nulliparous participants, the paracervical block also reduced pain (median 40 mm, IQR 25-53) compared with saline (median 50 mm, IQR 30-68) and capped needle (median 60 mm, IQR 33-70) (p < 0.001). Paracervical injection pain was minimal with a median of 1 out of 10 (IQR 0.00-2.00). Secondary outcomes demonstrated reduced patient pain at all timepoints of IUD insertion (eg, tenaculum placement, uterine sounding, and IUD insertion) as well as higher patient satisfaction (p < 0.01) in comparison to the capped needle group. CONCLUSIONS: The paracervical block reduced global pain score during IUD insertion, particularly for nulliparous participants, and is associated with minimal injection pain. IMPLICATIONS: Findings from this randomized, double-blind trial support incorporating the paracervical block into routine IUD insertion, especially for nulliparous patients who experience higher pain. Wider adoption may improve procedural comfort, satisfaction, and acceptability of IUD use. Future research should evaluate implementation, patient preferences, and variations in technique.