Bacteriuria and oral contraceptives. Routine health examinations of 12,076 middle-class women

The association of oral contraceptive use and urinary tract infection was studied in 12,076 middle-class women, aged 18 to 54 years, who came for routine health examination. The prevalence of bacteriuria, defined as two consecutive, positive (more than 100,000 colonies per milliliter) urine cultures, was 1.9% in the entire population studied and was 1.6%, 1.8%, and 2.4% in those never using oral contraceptives and past users and current users of oral contraceptives respectively. These differences were entirely accounted for by Escherichia coli infections. Higher prevalence was seen in users of oral contraceptives, respectively. These differences were entirely and pills with higher estrogen doses. There was no consistent pattern of rates by duration of oral contraceptive use nor with progestogen dose.