bials reduce the pelvic infection rate by 70 to 80 percent (Chelmow, 2001; Dinsmoor, 2009; Smaill, 2014). he observed benefit applies to both elective and nonelective incision infection rates.
Single-dose prophylaxis with a 2-g dose of ampicillin or a first-generation cephalosporin is ideal. Both equal the eicacy of broad-spectrum agents or multiple-dose regimens (American College of Obstetricians and Gynecologists, 2016b). For obese women, evidence supports a 3-g dose of cefazolin to reach optimal tissue concentrations (Swank, 2015). Extendedspectrum prophylaxis with azithromycin added to standard single-dose prophylaxis further reduced postcesarean metritis rates (Sutton, 2015; Ward, 2016). As noted earlier, Tita and colleagues (2016) reported that postoperative uterine infection was decreased from 12 to 6 percent with the addition of azithromycin to cefazolin. Women known to be colonized with MRSA are given vancomycin in addition to a cephalosporin (Chap. 64, p. 1223).
It is controversial whether the infection rate is lowered further if the antimicrobial is given before the skin incision compared with after umbilical cord clamping (Baaqeel, 2013; Macones, 2012; Sun, 2013). The American College of Obstetricians and Gynecologists (2016b) has concluded that the evidence favors predelivery administration. Abdominal preoperative skin preparation with chlorhexidine-alcohol is superior to iodine-alcohol for preventing surgical-site infections (Tuuli, 2016). Additive salutary efects may be gained by preoperative vaginal cleansing with povidone-iodine rinse or application of metronidazole gel (Haas, 2014; Reid, 2011; Yildirim, 2012).
Other Methods of Prophylaxis. Several studies have addressed the value of prenatal cervicovaginal cultures. These are obtained in the hope of identiying pathogens that might be eradicated to decrease incidences of preterm labor, chorioamnionitis, and puerperal infections. Unfortunately, treatment of asymptomatic vaginal infections has not been shown to prevent these complications. Carey and coworkers (2000) reported no beneficial efects for women treated for asymptomatic bacterial vaginosis. Klebanof and colleagues (2001) reported a similar postpartum infection rate in women treated for second-trimester asymptomatic Trichomonas vaginalis infection compared with that of placebo-treated women.