The evaluation of suspected late-onset sepsis in neonates and infants ≤6 months includes obtaining a sterile urine sample. Two techniques are used interchangeably in clinical practice to detect the presence of microorganisms: suprapubic aspiration (SPA) and urethral catheterization (UC). At present, it is unclear which method causes more pain. The primary objective of this systematic review and meta-analysis is to determine which technique is more painful.

Electronic databases were searched for relevant randomized and quasi-randomized trials in September 2023. Title and abstract screening, followed by data extraction, were performed in duplicate. The risk of bias was assessed using Cochrane’s risk of bias (RoB) 2.0 tool. The critically important outcome was pain measured using validated tools including unidimensional (behavioural) and multidimensional (combination of behavioural and physiological components) tools. Secondary outcomes included procedure success, procedure duration, and adverse events. Pooled effects estimates were standardized mean difference (SMD), mean difference (MD), and relative risk (RR) with 95% confidence intervals (CI) from random effects meta-analyses. Certainty assessment was completed using Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology.

Of the seven included studies, five studies reported pain scores among 378 infants. Clinical heterogeneity was noted across the studies specifically differences in postnatal age, procedure details (e.g., operator skillset, use of anesthetic and analgesic, ultrasound guidance), and pain assessment tools (unidimensional vs. multidimensional pain scores). There was no difference in pain score for overall procedure for SPA versus UC (SMD 0.25 [95% CI –0.63, 1.14], I² = 84%; n = 330) and duration of cry (MD 5.26 [95% CI –43.72, 54.23], I² = 97%; n = 245). The quality of evidence was low for these outcomes. There was a statistically significant difference in procedure duration when SPA was compared to UC (MD –62.62 [95% CI –112.96, –12.27], I² = 96%; n = 299) with SPA being the procedure of shorter duration. The quality of evidence for this outcome was moderate. None of the studies reported any serious adverse events.

There is insufficient evidence to recommend one technique over the other for reducing pain in infants ≤6 months. Healthcare professionals can select SPA or UC based on the unit preference, skillset, and available resources. Future research is required to inform clinical practice.