Chlorhexidine Versus Iodine for Vaginal Preparation Before Hysterectomy: A Randomized Clinical Trial.

OBJECTIVE:The American College of Obstetricians and Gynecologists does not provide a recommendation regarding the preferred vaginal preparation solution. We intended to compare the effectiveness of chlorhexidine versus iodine in decreasing vaginal bacterial counts. METHODS:In this institutional review board-approved study, participants undergoing total hysterectomy via vaginal or laparoscopic approach were randomized to 4% chlorhexidine or 10% iodine for presurgical vaginal preparation. Swabs were collected from the vaginal mucosa before, then 30, 60, and 90 minutes after preparation. Our primary outcome was the number of positive cultures (≥5,000 bacteria) at 90 minutes. The secondary outcomes included the presence of selected pathogens, postoperative complications, and infections. The sample size of 71 per arm was calculated using ɑP = 0.05, 80% power, and anticipating a 22% difference in positive cultures. RESULTS:Between May 2018 and August 2019, 85 participants were randomized. The average age was 59.8 years (SD, 11.4), and the median Charlson Comorbidity Index score was 2 (minimum, 0; maximum, 6). Baseline bacterial counts were similar in both groups. Chlorhexidine demonstrated a lower percentage of positive cultures at 90 minutes (47.6% vs 85.4%; odds ratio, 10.6; P = 0.001). In addition, the median bacterial count in the chlorhexidine group was significantly lower than the iodine group (3,000 vs 24,000 colony-forming units, P < 0.001) at 90 minutes. No surgical site infections were identified in either group during the 30-day postoperative period, and there were no reported adverse reactions to either solution. CONCLUSIONS:Chlorhexidine resulted in substantially lower bacterial counts after preparation compared with iodine. Gynecologic surgeons may consider switching to 4% chlorhexidine for vaginal preparation before hysterectomy.