For the time being, routine indwelling catheterisation of the bladder for caesarean section remains recommended

Sir, Li and Wen’s systematic review doesn’t show evidence of no effect, but only that there is no evidence of the effect of the placement of an indwelling catheter for caesarean section. As stated by the authors, the review lacks power to demonstrate any difference in important clinical outcomes between the catheterised versus the non-catheterised group. Urinary tract infection is a common but clinically less important outcome compared with possible serious perioperative complications, such as postpartum haemorrhage. Besides the methodological limitations of this review (recognised by the authors), the lack of data from clinically important outcomes undermines the rash conclusion that the routine use of indwelling urinary catheters for caesarean delivery patients is not necessary, and is even harmful. The non-randomised controlled trial included mentions that 6.7% of cases of postpartum uterine atony lead to haemorrhage! As stated by the authors, only 0.1% of obstetricians do not use urethral catheterisation, and obstetricians should continue to use (brief) catheterisation until there is evidence that catheterisation doesn’t improve important outcomes, even at the cost of more urinary tract infections. There is evidence that catheterisation for no longer than 12 hours doesn’t significantly increase the rate of urinary tract infections. As caesarean section is a frequently used intervention worldwide, even small differences for clinically important outcomes are worthy of study by methodologically sound randomised controlled trials, investigating the correct, important clinical questions. j