Effect of preoperative fasting on acute postoperative pain following cesarean section: a retrospective cohort study

Preoperative fasting is a cornerstone of Enhanced Recovery After Surgery (ERAS) protocols in cesarean delivery, primarily aimed at reducing aspiration risk. However, its impact on acute postoperative pain remains unclear. This study addresses a critical evidence gap regarding whether adherence to ERAS-compliant fasting guidelines influences post-cesarean pain intensity.

Data from 329 women who underwent cesarean sections at the hospital between March and December 2024 were retrospectively reviewed. Women were categorized based on adherence to ERAS fasting guidelines (≤8 h solids, ≤2 h clear fluids). The primary outcome was the 24-h postoperative Visual Analogue Scale (VAS) pain score. Univariate and multivariable linear regression models were used to assess the association between fasting compliance and VAS scores, adjusting for key covariates including age, body mass index, comorbidities, anesthesia type, surgical duration, and intraoperative morphine use.

Women adhering to ERAS fasting protocols had significantly lower mean 24-h VAS scores compared to non-adherent women (β = -0.6; 95% confidence interval: -1.2, -0.1; P = 0.029). This association remained significant after minor (β = -0.6; P = 0.046) and partial adjustment (β = -0.6; P = 0.038), though it attenuated to non-significance after full adjustment including epidural morphine (β = -0.5; P = 0.137). Subgroup analyses suggested consistent directional effects, but detailed subgroup results are reported in the main text.

Adherence to ERAS fasting guidelines is associated with a modest but statistically significant reduction in acute postoperative pain after cesarean section. While the clinical relevance of a 0.6-point VAS difference may be limited, these findings support integrating standardized preoperative fasting into obstetric ERAS pathways as a safe, low-cost component of multimodal pain management and enhanced recovery.