Asymptomatic bacteriuria in pregnancy: antibody-coated bacteria, renal function, and intrauterine growth retardation.

Asymptomatic bacteriuria (greater than 100,000 microorganisms per milliliter) was found in 70 of 1,400 pregnant women without symptoms referable to the urinary tract (five per cent). With the fluorescent antibody (FA) tests, antibody-coated bacteria were demonstrated in specimens from 35 patients (50 per cent), indicating silent renal bacteriuria. Although confirmation by direct localization methods was not feasible in this group of patients, indirect evidence of renal function impairment associated with the presence of antibody-coated bacteria was suggested by results of the serum creatinine and creatinine clearance tests. The outcome of the pregnancy was compared for patients with bacteriuria (FA-negative or FA-positive tests). An association between the presence of asymptomatic renal bacteriuria and intrauterine growth retardation was noted. Thus, the patient with asymptomatic bacteriuria and a positive FA test is at greater risk of delivering an intrauterine growth-retarded infant.