Objective  To evaluate the effect of neuraxial labor analgesia on energy metabolism, and analyze the mechanism of labor analgesia affecting energy metabolism, so as to provide energy-related support for promoting labor analgesia.

Methods  Totally 116 full-term primiparas who plan to practice natural birth in Beijing Haidian District Maternal and Child Health Care Hospital from October 2021 to August 2022 were recruited as study subjects. According to whether the parturients chose analgesia or not, they were divided into labor analgesia group (analgesia group) and non-labor analgesia group (control group), with 48 cases in each group. Hourly energy consumption, Numeric Rating Score (NRS) and heart rate, labor duration, delivery mode (forceps delivery or not), postpartum blood loss, the number of uterine inertia, neonatal Apgar score, umbilical cord blood gas analysis and other delivery outcome indicators were compared between two groups.

Results  Hourly energy consumption (141.22 ± 62.57) kcal/h, NRS 4(3 − 6) and heart rate (87.96 ± 12.65) beats/min at the first stage of labor and NRS 8(6 − 9) at the second stage of labor in analgesia group were significantly lower than those in control group (P < 0.05). Hourly energy consumption and heart rate at the second stage of labor, hourly energy consumption, NRS and heart rate at the third stage of labor were not different between two groups(all P > 0.05). The heart rate at the first stage of labor and NRS was positively correlated with time-sharing energy consumption (r = 0.829, P < 0.001; r = 0.389, P< 0.001), and heart rate was positively correlated with NRS (r = 0.268, P < 0.01). Delivery outcomes were not different between two groups(all P > 0.05).

Conclusion  Labor analgesia can significantly reduce energy consumption at the first stage of labor, which may be related to reduction of muscle tension, anxiety and circulatory stress caused by labor pain.