Objective  To assess whether infectious morbidity after total abdominal hysterectomy is decreased by the addition of 20 cc povidone–iodine gel at the vaginal apex after the usual vaginal preparation with povidone–iodine solution.

Study design  Randomised controlled trial.

Setting  Fifteen secondary and tertiary hospitals in Canada.

Sample  A total of 1570 women undergoing planned total abdominal hysterectomy.

Methods  Computer-generated randomisation using a centralised telephone service was stratified by study centre with variable block size. In the operating room, a swab for bacterial vaginosis was taken before vaginal antisepsis. Study group remained concealed until the standard surgical preparation in the operating room was complete. Then povidone-iodine gel 20 cc was placed at the vaginal apex in the intervention group only. Participants were followed for one month post-operative.

Main outcome measures  The primary outcome was post-operative infectious morbidity during the 30 days after surgery, defined as: febrile morbidity with hospital stay greater than five days or antibiotic treatment, or infection requiring readmission to hospital or additional visit. Other outcomes included abdominal wound infection, pelvic abscess and other pelvic infections.

Results  Post-operative infectious morbidity within 30 days occurred in 128/780 (16%) women receiving povidone–iodine gel preparation and 142/790 (18%) women not receiving gel (RR 0.9, 95% CI 0.7 to 1.1). Pelvic abscess was diagnosed in 0 patients in the gel group and in seven patients in the control group (P < 0.01). No significant difference was found in pelvic cellulitis (eight in each group) or abdominal wound infection (51 in the gel group and 58 in the control group, P= 0.5).

Conclusion  Povidone–iodine vaginal gel antisepsis led to a 9% relative decrease in overall infectious morbidity after abdominal hysterectomy, which was not statistically significant. Povidone–iodine vaginal gel decreased the risk of pelvic abscess after total abdominal hysterectomy.