Preoperative Hair Removal Methods and Surgical Site Infection Risk: A Cochrane Review

Hair removal with a razor prior to surgical operations likely results in increased surgical site infections (SSI), according to authors of an updated review published in The Cochrane Database of Systemic Reviews.

This was the second update of a review investigating whether SSI rates are affected by routine preoperative hair removal and the method, timing, or setting of hair removal. Investigators in the United Kingdom added 11 new studies comparing hair removal vs no hair removal, different methods of hair removal, and hair removal at different times before surgical operations. There were 25 studies included (19 randomized trials and 6 quasi-randomized trials) included in the review, with a total of 8919 participants.

The investigators found low-certainty evidence suggesting little difference in risk for SSI when hair is not removed, compared with removal using clippers (3 studies with 1733 participants; risk ratio [RR], 0.95;95% CI, 0.65-1.39). Based on moderate-certainty evidence, SSI risk is likely increased in patients undergoing hair removal with a razor compared with no removal (7 studies with 3723 participants; RR, 1.82; 95% CI, 1.05-3.14); this translates to an absolute risk for 17 additional SSIs per 1000. There was little difference in risk between depilatory cream removal and no removal (1 trial with 267 participants; RR, 1.02; 95% CI, 0.45-2.31), based on low-certainty evidence.

Moderate-certainty evidence suggested an increased SSI risk when hair is removed with a razor vs clipping (7 studies with 1706 participants; RR, 1.64; 95% CI, 1.16-2.33) and with a razor vs depilatory cream (RR, 2.28; 95% CI, 1.12-4.65). Based on low-certainty evidence, the investigators concluded that there may be a mild decrease in SSI risk in patients whose hair was removed on the day of the operation compared with the day before (1 study with 977 participants; RR, 0.83; 95% CI, 0.54-1.30).

According to the investigators, “there is the potential for further research in this area but trials would need to focus on areas of priority for patients and healthcare staff, [perhaps including] the impact of approaches to hair removal on specific anatomical regions, the timing of removal and the setting.”


Tanner J, Melen K. Preoperative hair removal to reduce surgical site infection. Cochrane Database Syst Rev. Published online August 26, 2021. doi:10.1002/14651858.CD004122.pub5