Date of Award

10-6-2009

Document Type

Open Access Thesis

Degree Name

Medical Doctor (MD)

First Advisor

Jessica Illuzzi

Second Advisor

Stephen Thung

Third Advisor

Ursula Brewster

Abstract

UTILITY OF REPEAT SCREENING FOR ASYMPTOMATIC BACTERIURIA IN PREGNANCY Sara Whetstone, Stephen Thung, and Jessica Illuzzi. Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale University, School of Medicine, New Haven, CT. Asymptomatic bacteriuria (ASB) during pregnancy is associated with an increased risk of developing pyelonephritis. The objectives of our study were to determine the incidence of ASB throughout the first two trimesters of pregnancy and to compare the cost effectiveness of performing repeat screening with a single screening strategy for ASB to prevent pyelonephritis. In this prospective cohort study, 206 pregnant women at an urban academic obstetric clinic provided urine for culture at monthly prenatal visits, and the incidence of ASB was calculated at 4 weeks intervals in the first and second trimesters. Descriptive statistics were calculated and used as baseline estimates in the cost-effectiveness analysis. Decision and cost-effectiveness analyses were performed. In the decision analysis, three strategies were compared: (1) no screening; (2) screening for ASB once in the first trimester; and (3) screening for ASB once in the first trimester and once between 18 and 22 weeks gestational age (GA). 9.71% of women were positive on initial screening culture for ASB. Among women with an initial negative culture, the incidence rate of ASB was 0% at less than 14 weeks GA, 1.1% between 14-18 weeks GA, 4.2% between 18-22 weeks GA, and 1.8% at greater than 22 weeks GA. The proportion of women identified with ASB on initial culture did not differ statistically from the proportion identified on repeat culture (McNemars test, p-value > 0.05). In the decision analysis, a policy of routine screening in the first and second trimester (2 urine culture strategy) was the dominant strategy compared to no screening and a single culture strategy. The model was robust in the sensitivity analysis.

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