Antimicrobial Prophylaxis Recommended for All Cesarean Deliveries

From Medscape Medical News
Laurie Barclay, MD

August 25, 2010 — The Committee on Obstetric Practice of the American College of Obstetricians and Gynecologists recommends antimicrobial prophylaxis for all cesarean deliveries unless the patient is already receiving appropriate antibiotics (eg, for chorioamnionitis), according to a Committee Opinion report in the September issue of Obstetrics and Gynecology. This antibiotic prophylaxis should be given within 60 minutes of starting the cesarean delivery.

"Antimicrobial prophylaxis for cesarean delivery has been a general practice for cesarean deliveries because it significantly reduces postoperative maternal infectious morbidity," the committee writes. "These antibiotics have been administered intraoperatively after umbilical cord clamping for two theoretic concerns related to the fetus:
1) antibiotics in neonatal serum may mask newborn positive bacterial culture results; and
2) fetal antibiotic exposure could lead to an increase in newborn colonization or infection with antibiotic-resistant organisms.
Recently, several randomized clinical trials investigated the timing of antimicrobial prophylaxis for cesarean delivery."

Based on surgical research data, antimicrobial prophylaxis to prevent surgical site infection should ideally begin within 30 minutes, and definitely within 2 hours, of skin incision.

For longer surgery, the same dose of antibiotic may need to be given again at intervals of 1 or 2 times the half-life of the drug. The review authors write that "preoperative [antibiotic] administration significantly reduces endometritis and total maternal infectious morbidity compared with administration of antibiotics after umbilical cord clamping."

Antimicrobial prophylaxis for cesarean delivery typically employs narrow-spectrum antibiotics, such as a first-generation cephalosporin, effective against gram-positive bacteria, gram-negative bacteria, and some anaerobic bacteria. A single 1-g intravenous dose of cefazolin usually results in a therapeutic level for 3 to 4 hours, but obese women may need larger doses.

Clindamycin with gentamicin is a reasonable option for women with a significant allergy to β-lactam antibiotics, such as cephalosporins and penicillins.

Studies to date suggest that preoperative antimicrobial prophylaxis does not appear tohave any harmful effects on the mother or infant, nor is it associated with an increase in neonatal infectious morbidity or selection of antimicrobial-resistant bacteria causing neonatal sepsis. However, additional prospective evaluation is needed because these studies lacked sufficient power to assess those outcomes.

"The Committee on Obstetric Practice recommends antimicrobial prophylaxis for all cesarean deliveries unless the patient is already receiving appropriate antibiotics (eg, for chorioamnionitis) and that prophylaxis should be administered within 60 minutes of the start of the cesarean delivery," the committee concludes. "When this is not possible (eg, need for emergent delivery), prophylaxis should be administered as soon as possible."

Obstet Gynecol. 2010;116:791-792.