Antibiotic prophylaxis regimens and drugs for cesarean section

Prophylactic antibiotics for cesarean section have been shown to reduce the incidence of maternal postoperative infectious morbidity. Many different antibiotic regimens have been reported to be effective.

The objective of this review was to determine which antibiotic regimen is most effective in reducing the incidence of infectious morbidity in women undergoing cesarean section.

We searched the Cochrane Pregnancy and Childbirth Group trials register and the Cochrane Controlled Trials Register. The date of the most recent search was October 1998.

Randomized trials that included women undergoing cesarean section were included. Trials were required to compare at least two different antibiotic regimens. Trials that compared placebo with a single antibiotic regimen were not included as these are studies which have been analyzed in another Cochrane review.

Data were extracted from each publication independently by the reviewers. Reviewers were not blinded to the authors or sources of the articles. The primary outcome variable was endometritis but data on other infectious complications were collected where provided.

Fifty-one trials published between 1979 and 1994 were included in the review and four were excluded from the review. The following results refer to reductions in the incidence of endometritis. Both ampicillin and first generation cephalosporins have similar efficacy with an odds ratio (OR) of 1.27 (95% confidence interval (CI): 0.84-1.93). In comparing ampicillin with second or third generation cephalosporins the odds ratio was 0.83 (95% CI 0.54-1.26) and in comparing a first generation cephalosporin with a second or third generation agent the odds ratio was 1.21 (95% CI 0.97-1.51). A multiple dose regimen for prophylaxis appears to offer no added benefit over a single dose regimen; OR 0.92 (95% CI 0.70-1.23). Systemic and lavage routes of administration appear to have no difference in effect; OR 1.19 (95% CI 0.81-1.73). There was no significant heterogeneity between the trials contained in the various sub-group analyses, although confidence intervals were sometimes wide.

Both ampicillin and first generation cephalosporins have similar efficacy in reducing postoperative endometritis. There does not appear to be added benefit in utilizing a more broad spectrum agent or a multiple dose regimen. There is a need for an appropriately designed randomized trial to test the optimal timing of administration (immediately after the cord is clamped versus pre-operative).