The effectiveness of blood testing in the management of pyelonephritis in pregnancy for improving outcomes

Urinary tract infections (UTIs) are a common infection among women, with most women having developed a UTI at least once in their lifetime. Pyelonephritis, a UTI which affects the upper urinary tract and kidneys, is one of the most prevalent conditions that require hospitalisation among pregnant women. In general, both urine and blood samples are taken for diagnosis and to tailor the necessary antibiotic therapy to the needs of the patient. Some severe cases of pyelonephritis require hospitalisation and intravenous administration of antibiotics. Several previous studies have reported that excluding blood testing or 'blood culture' samples and using only urine samples in managing the condition could be as safe and effective as the current approach, in which both urine and blood samples are analysed. Previous research has also suggested that urine samples render blood samples superfluous, as blood samples offer no additional clinical value for the management of pyelonephritis. Testing only urine samples could also be significantly cost-saving.

This review aims to evaluate the effectiveness of routine blood cultures in the management of pyelonephritis in pregnancy. However, we did not identify any data from randomised controlled trials in order to examine the efficacy of routine blood cultures in the management of the condition among pregnant women. Further research is required to assess the effectiveness of managing pyelonephritis in pregnant women with or without blood culture samples, as well as to address possible adverse outcomes and the potential cost-effectiveness of excluding blood cultures from treatment.

Authors' conclusions: 

There are no large-scale randomised controlled trials to assess outcomes in the management of pyelonephritis in pregnancy with or without blood cultures. Randomised controlled trials are needed to evaluate the effectiveness of managing pyelonephritis in pregnant women with or without blood cultures, and to assess any adverse outcomes as well as the cost-effectiveness of excluding blood cultures from treatment.

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Background: 

Pyelonephritis is a type of urinary tract infection (UTI) that affects the upper urinary tract and kidneys, and is one of the most common conditions for hospitalisation among pregnant women, aside from delivery. Samples of urine and blood are obtained and used for cultures as part of the diagnosis and management of the condition. Acute pyelonephritis requires hospitalisation with intravenous administration of antimicrobial agents. Several studies have questioned the necessity of obtaining blood cultures in addition to urine cultures, citing cost and questioning whether blood testing is superfluous. Pregnant women with bacteraemia require a change in the initial empirical treatment based on the blood culture. However, these cases are not common, and represent approximately 15% to 20% of cases. It is unclear whether blood cultures are essential for the effective management of the condition.

Objectives: 

To assess the effectiveness of routine blood cultures to improve health outcomes in the management of pyelonephritis in pregnant women.

Search strategy: 

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register without language or date restrictions (31 December 2014).

Selection criteria: 

Randomised controlled trials and quasi-randomised trials comparing outcomes among pregnant women with pyelonephritis who received initial management with or without blood cultures. Cluster-randomised trials were eligible for inclusion in this review but none were identified. Clinical trials using a cross-over design were not eligible for inclusion.

Data collection and analysis: 

Two review authors independently assessed one trial report for inclusion.

Main results: 

We identified one trial report but this was excluded. No clinical trials met the inclusion criteria for this review.