Mepivacaine instillation for pain reduction during intrauterine device placement in nulliparous women: a double-blinded randomized trial.

BACKGROUND

Fear of pain associated with intrauterine device (IUD) placement has been identified as a significant barrier to the adoption of long-acting reversible contraception, contributing to lower utilization of the most effective reversible contraceptive methods.

OBJECTIVE

To assess whether instillation of intrauterine mepivacaine before IUD placement alleviates pain more effectively than a placebo.

STUDY DESIGN

We conducted a multicenter, double-blind, randomized, placebo-controlled trial involving nulliparous women undergoing IUD placement. An intrauterine instillation of 10 mL of 20 mg/mL mepivacaine or 0.9 mg/mL sodium chloride was administrated through a hydrosonography catheter 2 minutes prior to IUD placement. Pain scores were assessed using a 100 mm visual analog scale (VAS) at prespecified time points. Primary outcome measured the difference in VAS pain scores between the intervention group and the placebo group during IUD placement. Secondary outcomes included VAS pain scores at instillation and 10 minutes after placement, tolerability of the placement pain, as well as acceptability of the analgesia method.

RESULTS

We enrolled 151 participants, with 76 assigned to the mepivacaine group and 75 to the placebo group. The mean VAS pain score during IUD placement showed a difference of 13.3 mm (95% confidence interval (CI) 5.75-20.87; P<.001): the mepivacaine group had a mean of 53.9 mm (standard deviation [SD] 22.8), while the placebo group had a mean of 67.2 mm (SD 22.4). After adjusting for each individual provider's impact, the difference in mean pain scores remained statistically significant (12.2 mm 95% CI 4.85-19.62; P<.001). A greater proportion of women in the intervention group reported tolerable pain during placement with 70/75 participants (93.3%) compared to 53/66 participants (80.3%) in the placebo group (P=.021).

CONCLUSION

The intrauterine instillation of mepivacaine results in statistically significant reduction in pain score among nulliparous women during IUD placement. Although the precise clinical impact of this pain reduction method remains uncertain, the observed reduction in pain score result in a higher proportion of women reporting tolerable pain. This finding and the high acceptance as a pain reduction method thereby suggests clinical relevance. Intrauterine instillation of mepivacaine is a possible strategy to increase IUD utilization, particularly among nulliparous women who are at high risk of unintended pregnancy.