Intrauterine mepivacaine instillation for pain relief during intrauterine device insertion in nulliparous women: a double-blind, randomized, controlled trial.
OBJECTIVE
To evaluate whether intrauterine mepivacaine instillation before intrauterine device (IUD) insertion decreases pain compared to placebo.


STUDY DESIGN
We performed a double-blind, randomized, controlled trial comparing mepivacaine 1% 10 mL versus 0.9% NaCl intrauterine instillation using a hydrosonography catheter 5 min before IUD insertion in women 18 years of age or older. Participants completed a series of 10-cm visual analogue scales (VAS) to report pain during the procedure. The primary outcome was the difference in VAS scores with IUD insertion between intervention group and placebo. Secondary outcomes included VAS before and after insertion and analgesia method acceptability.


RESULTS
We randomized 86 women in a 1:1 ratio; both groups had similar baseline characteristics. In the intention-to-treat analysis, the primary outcome, median VAS with IUD insertion, was 4.8 cm in the intervention group [n=41, interquartile range (IQR) =3.1-5.8] and 5.9 cm in the placebo group (n=40, IQR=3.3-7.5, p=.062). In the per-protocol analysis, the median VAS with IUD insertion was 4.8 cm (IQR=3.1-5.5) and 6.0 cm (IQR=3.4-7.6) for the intervention and placebo groups, respectively (p=.033). More women in the intervention group reported the procedure as easier than expected (n=26, 63.4% vs. n=15, 37.5%), and fewer reported it as worse than expected (n=3, 7.3% vs. n=14, 35%, p=.006).


CONCLUSION
Intrauterine mepivacaine instillation before IUD insertion modestly reduces pain, but the effect size may be clinically significant.


IMPLICATIONS STATEMENT
While the reduction in VAS pain scores did not meet our a priori difference of 1.3 points for clinical significance, participants' favorable subjective reaction suggests that this approach merits further study.
['Envall|Niklas|N|', 'Lagercrantz|Helena Graflund|HG|', 'Sunesson|Jessica|J|', 'Kopp Kallner|Helena|H|']
D000282:Administration, Intravaginal D000293:Adolescent D000328:Adult D000779:Anesthetics, Local D004311:Double-Blind Method D005260:Female D006801:Humans D007434:Intrauterine Devices D008619:Mepivacaine D010146:Pain D010147:Pain Measurement D058748:Pain Perception D013548:Sweden D013997:Time Factors D064232:Visual Analog Scale D055815:Young Adult
Mepivacaine Pain Intrauterine devices VAS Contraception