Risk factors for infection at the operative site after abdominal or vaginal hysterectomy

We studied risk factors for postoperative infections at the operative site after hysterectomies. Data were collected prospectively on all women undergoing vaginal hysterectomies (323 patients) or abdominal hysterectomies (1125 patients) at the Boston Hospital for Women between February 1976 and April 1978. Logistic-regression analysis indicated that factors significantly associated (P less than 0.05) with a higher risk of infection at the operative site were increased duration of operation, lack of antibiotic prophylaxis, younger age, being a clinic patient, and an abdominal approach. After these variables were accounted for, the variables of obesity, preoperative functional and anatomical diagnoses, postoperative anatomical and pathological diagnoses, estimated blood loss, menopausal status, and operation by a specific surgeon did not add predictive power. An increasing duration of operation was associated with a decreasing effect of antibiotic prophylaxis, the preventive fraction of which diminished from 80 per cent at one hour to an unmeasurable effect at 3.3 hours.