Decreasing incidence of postcesarean endometritis with extended-spectrum antibiotic prophylaxis.
OBJECTIVE
To describe the effect of an extended-spectrum prophylactic antibiotic regimen on postcesarean endometritis.


METHODS
This is a cohort study of trends in postcesarean endometritis using data both from prospective surveillance by the infection control unit and from query of our obstetric computerized database to compare three periods of antibiotic prophylaxis: standard narrow-spectrum with intravenous first- or second-generation cephalosporin (1992-1996), clinical trial of extended-spectrum with addition of intravenous doxycycline and oral azithromycin (1997-1999), and routine use of extended-spectrum with addition of intravenous azithromycin (2001-2006) to standard cephalosporin prophylaxis.


RESULTS
A total of 48,913 deliveries at 24 weeks or more of gestation occurred from 1992 to 2006, of which 10,966 (22.4%) were cesarean deliveries. Annual cesarean rates increased from 16% to 27.5%. Trends in the incidence of postcesarean endometritis revealed a biphasic decrease consistent with the phased introduction of extended-spectrum prophylaxis. Incidence (95% confidence interval [CI]) of endometritis by prospective surveillance dropped from 19.9% (95% CI 18.6-21.3%) to 15.4% (95% CI 13.2-17.9%) during the clinical trial period: relative risk (RR) 0.77 (95% CI 0.66-0.91), P=.002; and then to 6.3% (95% CI 5.0-7.9%) during routine use of extended-spectrum prophylaxis: RR 0.41 (95% CI 0.31-0.54), P<.001. Corresponding incidence by database query dropped from 23% (95% CI 21.5-24.4%) to 16% (95% CI 14.4-17.9%): RR 0.69 (95% CI 0.61-0.79), P<.001; and then to 2.1% (95% CI 1.8-2.6%): RR 0.13 (95% CI 0.11-0.16), P<.001. These findings were unchanged after adjusting for potential confounders.


CONCLUSIONS
Extended-spectrum antibiotic prophylaxis involving the addition of azithromycin to standard narrow-spectrum prophylaxis was associated with a significant reduction in postcesarean endometritis.


METHODS
II.
Tita
Alan T N
AT
Department of Obstetrics & Gynecology, and Infection Control Unit, UAB Hospital, University of Alabama at Birmingham, Birmingham, Alabama, USA. alan.tita@obgyn.uab.edu
Hauth
John C
JC
Grimes
Anne
A
Owen
John
J
Stamm
Alan M
AM
Andrews
William W
WW
D000328:Adult; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D019072:Antibiotic Prophylaxis / Q000379:methods*; D017963:Azithromycin / Q000627:therapeutic use*; D002511:Cephalosporins / Q000627:therapeutic use; D002585:Cesarean Section / Q000009:adverse effects*; D015331:Cohort Studies; D004716:Endometritis / Q000209:etiology / Q000517:prevention & control*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D011247:Pregnancy; D011645:Puerperal Infection / Q000517:prevention & control*; D012189:Retrospective Studies; D012306:Risk; D013530:Surgical Wound Infection / Q000517:prevention & control*
D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D017963:Azithromycin