Pregnancy outcome following bacteriuria in pregnancy and the significance of nitrites in urinalysis-a retrospective cohort study

The association between bacteriuria and adverse pregnancy outcomes has been extensively described. The current practice of screening all pregnant women for bacteriuria is challenged by recent studies. We aimed to evaluate pregnancy outcomes among women with a positive urine culture, to assess the significance of positive urinary nitrites in this setting. This was a retrospective cohort study at the emergency department (ED) of the Helen Schneider Hospital for Women, Israel, during 2014-2018. This included all gravida women >18 years old within the 20^th week of pregnancy or above, admitted to the ED with diverse complains, who had urinalysis collected and subsequently had a positive urine culture. Clinical and obstetric characteristics were stratified by positive vs. negative nitrites in urinalysis. The primary outcome was premature delivery, and the secondary outcomes were a composite outcome of all recorded pregnancy complications and the significance of urinalysis in predicting urinary tract infection (UTI). Overall, 874 pregnant women with a positive urine culture were included. Of them, 721 (79%) patients had a negative nitrite in their urine exam (NNU-group) and 153 (21%) had a positive nitrite in their urine exam (PNU-group). Escherichia coli was the most common pathogen, with significantly higher rates of growth in the PNU-group vs. NNU-group [129 (84.3%) vs. 227 (38.4%), P < 0.001]. Premature delivery was recorded with no association of symptomaticity or nitrite status. Among symptomatic women with classic symptoms of UTI, PNU was significantly associated with decreased risk for major peripartum complications [odds ratio (OR) with 95% confidence interval (CI) of 0.22 (0.05-0.94)]. Our findings support that PNU among symptomatic pregnant women with UTI-related symptoms was associated with lower risk of developing major adverse obstetrical outcomes.