Surgical site infection following elective Caesarian section: a case-control study of postdischarge surveillance

To ascertain the incidence of postoperative surgical site infection (SSI) following elective Caesarean section (CS) and to compare demographic characteristics and antibiotic administration between infected cases and noninfected control subjects.

We conducted a retrospective case-control study of patients undergoing elective CS between 1996 and 2002 at a tertiary centre. Infection-control personnel attempted to contact by telephone all women who had had Caesarean sections, 1 month after their surgery. The women they reached were asked to complete a questionnaire based on CDC-validated criteria for infection to determine whether SSI had occurred. Control subjects without SSI were matched on the basis of having had an elective CS and by date of surgery. We then reviewed the hospital records of both groups.

Over the study period, 1250 elective Caesarean sections were performed and 124 infected cases were identified, giving an overall SSI incidence of 9.9%. Of the 342 women reviewed (124 cases, 218 control subjects), 23% received prophylactic intraoperative antibiotics. Cases and control subjects differed significantly in terms of estimated blood loss, with fewer control subjects having excessive blood loss (P = 0.04). Among those women receiving postoperative antibiotics, case subjects received a significantly higher number of doses than did control subjects (P = 0.003). The groups did not differ significantly in terms of overall antibiotic administration or other demographic variables.

The incidence of SSI following elective CS according to postdischarge surveillance was 9.9%, which is higher than expected for a low-risk procedure. Because follow-up was not possible for all cases, this incidence may be an underestimate. Underuse of antimicrobial prophylaxis may also be a contributing factor, because prophylactic antibiotics were administered in less than 25% of cases.