The Skin Prep Study

The investigators propose a randomized controlled clinical trial to determine the comparative effectiveness of chlorhexidine-alcohol and iodine-alcohol preoperative skin preparation for preventing surgical site infections at cesarean section. While estimates vary, surgical site infections complicate up to 5 - 10% of all cesarean sections and result in significant human suffering and excess health care costs. Interventions such as preoperative antibiotic prophylaxis reduce surgical site infections by 60%, but the rate of infection remains high. There is therefore a great need to identify and test other potential interventions to further reduce these infections. The skin is a major source of pathogens that cause surgical site infection. Therefore, optimizing preoperative skin antisepsis has the potential to decrease postoperative surgical site infections. There is paucity of evidence to guide the choice of antiseptic for skin preparation at cesarean section. To date, only two underpowered trials have been published comparing two methods of preoperative skin preparation at cesarean section. A recent randomized trial in adults undergoing clean-contaminated mostly general surgical procedures demonstrated a 41% reduction in surgical site infection with the use of chlorhexidine-alcohol when compared to the more commonly used povidone-iodine. While it is plausible that findings from trials in other clean-contaminated surgical procedures may apply to cesarean sections, physiological changes in pregnancy, the peculiar dual microbial source for cesarean-related infections and the hormone-mediated immune-modulation in pregnancy make the validity of such extrapolation uncertain. The study has the following specific aims: Primary Aim: To test the hypothesis that preoperative chlorhexidine-alcohol skin preparation at cesarean section significantly reduces surgical site infections compared to iodine-alcohol. Secondary Aim 1: To test the hypothesis that preoperative chlorhexidin