Effect of inhibition of pain axis conduction on maternal gastric emptying during labor: a prospective controlled study

Background: The pain during labor is severe, and epidural analgesia is often used to inhibit pain axis conduction at present. Diet management during labor is very important during the whole process of labor. Therefore, we compared gastric emptying of semi-solid food between parturient women undergoing versus not undergoing epidural analgesia. Methods Seventy full-term, low-risk parturients were selected and divided into two groups according to epidural analgesia status: epidural analgesia group (LA, n= 35) and non-epidural analgesia group (NA, n= 35). The cross-sectional area of the gastric antrum (CSA ₀ ) was measured while fasting using B-ultrasound, and the time recorded as T0. The parturients in both groups then ate about 300 g millet congee (about 600 KJ). The CSAs of the gastric antra were measured by ultrasonography 60, 90, and 120 minutes after the experimental meal, these areas being recorded as CSA ₁ , CSA ₂ and CSA ₃ and the corresponding time points as T1, T2, and T3. Pain scores of parturients at these four time points were recorded. Gastric emptying time was also recorded. Results CSA ₁ , CSA ₂ , and CSA ₃ were larger in the NA than in the LA group, and the gastric emptying time was longer in the NA than in the LA group (P<0.05). Pain scores were higher in the NA than LA group at the three time points of T1, T2, T3 (P<0.05). Conclusions Inhibition of the pain axis conduction by epidural analgesia can promote gastric emptying during labor. Therefore, semisolid food intake during vaginal delivery does not increase the risk of vomiting and aspiration in women undergoing labor analgesia compared with women without labor analgesia.