HARP Trial: Hysteroscopy Anesthesia for Relief of Pain

This randomized clinical trial aims to evaluate the effect of local anesthesia on pain perception in patients undergoing outpatient diagnostic hysteroscopy. Although generally well tolerated, pain during hysteroscopy remains a leading cause of procedural failure and patient discomfort. Current evidence on the effectiveness of local anesthetic techniques is limited, with considerable variability in study designs, patient populations, and outcomes measured.

This study will compare pain levels between two groups: one receiving local anesthetic infiltration (3% mepivacaine into the uterosacral ligaments), and the other undergoing a placebo-like intervention (saline irrigation without injection). Pain will be assessed using a standardized Visual Analog Scale (VAS).

The primary objective is to determine whether local anesthesia significantly reduces pain perception during the procedure. Secondary objectives include evaluating which patient or procedural variables may influence pain (e.g., parity, uterine position, BMI, operator experience) and whether local anesthesia impacts the need for post-procedural analgesia or complication rates.

Patients will be randomly assigned in a 1:1 ratio using a simple randomization method. Although the study design does not allow for double blinding, efforts will be made to minimize expectation bias-patients will not be explicitly informed whether they are receiving anesthesia or not, and the placebo group will receive simulated intervention. The principal investigator and the statistician will be blinded to the treatment allocation during data analysis.

Inclusion criteria are: age ≥ 18 years, indication for office-based diagnostic hysteroscopy or minor operative procedures (e.g., polypectomy or biopsy), and no previous hysteroscopy experience. Exclusion criteria include known anesthetic allergy, complex procedures (e.g., myomectomy), anatomic uterine malformations, severe complications, or lack of consent.

A total sample size of 58 patients (29 per group) has been calculated based on an expected clinically relevant VAS difference of 1.5 points and a standard deviation of 2.0. To account for possible dropouts, up to 70 patients may be enrolled.

The results of this trial will provide higher quality evidence on whether local anesthesia should be routinely recommended in outpatient hysteroscopy and may support cost-effectiveness studies in the future.