Uterine flora at cesarean and its relationship to postpartum endometritis

To evaluate the relationship between the presence of microorganisms at the time of cesarean at different sites of the genital tract and the development of postpartum endometritus.

One-hundred thirty-three healthy women who delivered by cesarean were enrolled in this prospective study. Cultures were obtained during the surgery and on days 3-5 postoperatively. Gram staining of uterine cavity fluid was done on days 3-5. Gram stains were examined under a high-power microscope for the presence of polymorphonuclear leukocytes.

Twenty patients (15.0%) met the criteria for postpartum endometritis. Forty-five patients (33.8%) had one or more positive cultures (n = 133) at the time of surgery, resulting in 93 positive cultures and 123 bacterial isolates. Forty-four patients had positive postoperative uterine cavity cultures at days 3-5 postpartum, resulting in 65 isolates. Of 44 patients with a positive postoperative culture, 26 (59.1%) also had Gram stain positive for polymorphonuclear leukocytes in the uterine cavity fluid, whereas only six of 89 patients (6.7%) with negative postoperative culture had a positive Gram stain (P < .05). The relative risk of having a positive culture on postoperative day 3-5 if the culture at surgery was positive at any site was 15.6 (95% confidence interval [CI] 5.9, 42.2), and it was 19.5 (95% CI 6.8, 57.8) if the culture was positive at the lower uterine segment.

The presence of bacteria in the lower uterine segment at the time of the surgery predicts their presence in the uterine cavity during puerperium. The Gram stain of uterine cavity fluid on postcesarean days 3-5 is another quick tool that can expedite the diagnosis of postpartum endometritis.