The Proper Timing of Prophylactic Antibiotics for Caesarian Section

September 12, 2007

SMFM 27th Annual Meeting 2007

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read the abstract: Administration of Cefazolin Prior to Skin Incision is Superior to Cefazolin at Cord Clamping in Preventing Post-Cesarean Infectious Morbidity


My name is Scott Sullivan. I am an Assistant Professor of Maternal Fetal Medicine and a Residency Program Director at the Medical University of South Carolina in Charleston. I am here at the Society for Maternal Fetal Medicine annual meeting to present our research entitled, The Administration of Cefazolin Pre-Operatively is Superior to Administration at Time of Cord Clamping for the Prevention of Post-Cesarean Infectious Morbidity: A Randomized Controlled Trial.

There is a controversy that exists regarding the proper timing of prophylactic antibiotics for cesarean section. Cesarean section is known to be a significant risk for maternal infection, including endo-myometritis, wound infection and others. The current practice in the United States is to administer antibiotics at the time of cord clamping for theoretical neonatal concerns. However, these have never been proven.

Our hypothesis for this trial was that administration of antibiotics before surgery would result in fewer infectious events in the mothers than if it were given at the time of cord clamping without an increase in neonatal risks. Our trial was a prospective, randomized, double-blind, placebo-controlled trial. We enrolled 357 subjects over a two-year period, which met our planned power analysis. Essentially, there were two bags of fluid, one which was just normal saline or the placebo bag, and one which contained the antibiotic. One was given for 60 minutes pre-operatively and one bag given at the time of cord clamping. The patients were followed for six weeks and the clinical criteria for endo-myometritis or wound infection were used for diagnosis, infectious events.

Our results indicated that in the pre-operative group, there was a statistically significant decrease in the instances of endo-myometritis, as well as total infectious events. There was a 50% decrease in wound infections, as well, but it did not represent a statistical significance. There was no difference between groups in the demographic variables or obstetric variables and in the neonatal outcome; there was no difference in sepsis, in septic work-ups, in ICU admissions.

So we concluded from these results that administration of antibiotics pre-operatively would decrease the incidence of cesarean infections without increasing neonatal risk. We plan as a follow-up study, to do a multi-center trial across different populations to try to confirm these initial findings.