Are there differences in pain intensity between two consecutive vaginal childbirths? A retrospective cohort study

Background: Pain assessment is crucial for in-labour pain management. Even though women's self-rated pain intensity is the standard for pain relief or analgesic administration, multiparas appear to receive worse in-labour pain management than primiparas do. The discrepancy in pain perception between primiparas and multiparas remains unclear. Healthcare providers tend to think that multiparas endure the pain and report less pain because they have experienced childbirth. Objective: To retrospectively analyse the intensity of in-labour pain during first and second vaginal childbirth within the same group of women and explore whether parity may be an influential factor in labour pain intensity. Design: Retrospective cohort study. Setting: Labour and delivery in a large academic specialized hospital in Guangzhou, China. Participants: Women were included if they had two consecutive vaginal childbirths with singleton cephalic presentations and cervical dilation <= 3 cm for the first childbirth and <= 2 cm for the second childbirth. The final study sample consisted of 417 women. Methods: All childbirth case records between January 2015 and August 2018 were scanned using a structured electronic medical system. Maternal and neonatal demographics as well as obstetric and neonatal outcomes were extracted. The in-labour pain for each childbirth was compared between first and second births. Paired t-tests, McNemar's chi-square tests and mixed-effects modelling were applied to compare the differences in labour pain intensity between the two vaginal childbirths and explore the factors that influenced maximum labour pain scores during the second childbirth. Results: Four hundred seventeen women were included, with an average birth interval of 1.7 years. The average maximum labour pain score during the latent phase was 6 (5,6) for the first childbirth and 5 (4,6) for the second childbirth (paired t =-6.13, P <0.001). Pain scores decreased in 28.1% (117/417) of women and increased in 13.7% (57/417) of women from the first to the second childbirth. More than half of the women in our study experienced the same maximum labour pain score during the first and second labour. Mixed-effects modelling revealed that parity, education and pregnancy complications were independently associated with maximum labour pain scores. Conclusions: From a clinical point of view, in-labour pain is not clinically different for women when comparing their first and second labours. Health care professionals may underestimate in-labour pain in primiparas when comparing them with nulliparas. More studies are warranted to explore options for achieving better pain management for women with more childbirths. (C) 2020 Elsevier Ltd. All rights reserved.