Objective: To identify predictors of symptomatic urinary tract infection (UTI) after 20 weeks' gestation.
Study design: A retrospective cohort analysis was conducted of all deliveries at three North Carolina hospitals between 1990 and 1993. A total of 7403 deliveries remained after exclusions (pre-pregnancy diabetes, HIV-positive, structural urologic abnormalities, no prenatal care) and restrictions (black or white race, county of residence). Cystitis and pyelonephritis were identified by clinician diagnosis. Multiple logistic regression was conducted.
Results: Prior UTIs (both before and earlier in pregnancy), nonprivate clinics, and a history of chlamydia (white women only) doubled the risk of symptomatic UTIs after 20 weeks' gestation. The strongest predictor of pyelonephritis was prior antenatal UTIs (adjusted incidence odds ratio = 5.3, 95% confidence interval of 2.6-11.0), followed by less education (< 12 years), a history of chlamydia, nonprivate clinics, illicit drug use, sickle cell hemoglobinopathy, and being unmarried.
Conclusion: Medical history and demographic factors predict cystitis and pyelonephritis after 20 weeks' gestation. Prospective studies of pyelonephritis predictors and screening strategies are warranted.