The clinical utility of intrapartum screening urinalysis for the prevention of postpartum pyelonephritis

Abstract

Objectives: Urinary tract infection (UTI) is the most common bacterial infection to complicate pregnancy. Medical authorities recommend screening for asymptomatic bacteriuria (ASB) in pregnancy; albeit there is no consensus on ideal timing and frequency for testing. Due to the persistent physiologic changes of pregnancy postpartum, a recent trend to perform urinalysis upon presentation for delivery has been adopted at our institution and various satellite hospitals to putatively minimize cases of postpartum pyelonephritis. The aim of this study is to examine whether routine testing with urinalysis and screening for ASB following suspicious urinalysis with treatment can decrease the incidence of postpartum pyelonephritis, and to determine whether certain urinalysis parameters are more predictive of a positive urine culture.

Study design: A retrospective chart review study of all term deliveries was conducted over two years at the American University of Beirut Medical Center, a university teaching hospital. A total of 2359 deliveries of women with no increased susceptibility to UTIs were reviewed. None had urinary symptoms upon presentation. Urinary parameters including time of urinalysis and urine culture collection with respect to time of delivery, corresponding results and mode of urine collection were correlated to intrapartum course, incidence of ASB and of postpartum pyelonephritis.

Results: The incidence of ASB among women presenting for delivery was 4.83 %, with Escherichia coli as the most commonly detected pathogen. The presence of nitrite on urinalysis was significantly associated with a positive urine culture (p-value<0.001). Women with history of antenatal ASB or UTI were more likely to have ASB intrapartum with an odds ratio of 3.14 (95 % CI 1.71-5.75, p-value <0.001). Intrapartum urinalysis with subsequent diagnosis and treatment of ASB did not significantly affect the incidence of postpartum pyelonephritis (p-value 0.280). Similarly, intrapartum urinalysis in the setting of positive history of antenatal ASB or UTI did not increase the incidence of postpartum pyelonephritis compared to women with no such history (p-value 0.659).

Conclusions: Urinalysis screening intrapartum does not decrease the incidence of postpartum pyelonephritis. Universal urinalysis screening intrapartum is not warranted and should be reserved for women reporting urinary symptoms and/or women at high risk of UTI.

Keywords: Asymptomatic bacteriuria; Pregnancy; Pyelonephritis; Screening; Urinalysis; Urinary tract infections; Urine culture.