The effect of using lubricant for vaginal speculum insertion on the rate of unsatisfactory results of Pap smear: a systematic review and meta-analysis

BACKGROUND: Cervical cancer affects approximately 620,000 women annually and remains a leading cause of cancer mortality, particularly in low-resource settings. This meta-analysis evaluates whether lubricant use during vaginal speculum insertion affects unsatisfactory cytologic results in Pap smear procedures. METHODS: We systematically searched WoS/ISI, PubMed/MEDLINE, Scopus, Google Scholar, and Cochrane databases. RCTs and cohort studies were analysed in separate subgroup analyses per Cochrane Handbook recommendations. Quality was assessed using the Newcastle-Ottawa Scale and Cochrane RoB 2 tool; evidence certainty was rated via GRADE. Sensitivity analyses and publication bias assessment (funnel plots, Egger's test) were performed. RESULTS: Of 2,112 identified records, 14 studies comprising 18,681 women (7,757 lubricant; 10,924 control) met inclusion criteria (Cohen's Kappa = 0.79). Overall, water-based lubricant did not significantly affect unsatisfactory Pap smear rates (OR = 1.14, 95% CI: 0.90-1.44; P = 0.280; I² = 38.74%). Subgroup analysis confirmed no significant impact in RCTs (OR = 0.83, 95% CI: 0.58-1.16; P = 0.253; I² = 0%), while cohort studies showed a borderline trend toward increased rates (OR = 1.37, 95% CI: 0.98-1.90; P = 0.062; I² = 59.98%). A non-significant trend toward pain reduction was observed (SMD = - 0.77, 95% CI: -1.55 to 0.01; P = 0.054); however, extreme heterogeneity (I² = 94.21%) precludes reliable interpretation. CONCLUSIONS: Lubricant use does not compromise Pap smear adequacy based on RCT evidence of moderate certainty; the borderline cohort trend is of low certainty and should be interpreted with caution. Pain evidence is inconsistent and highly heterogeneous; no clinical recommendation regarding patient comfort can be made. Large-scale standardized RCTs examining LSIL/HSIL detection are warranted. These findings support cautious guideline consideration of lubricant use pending higher-certainty evidence.