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Background and Aims Sub-acute pain after childbirth (SAPC) can escalate to chronic pain, impairing maternal well-being. Central sensitisation, a major pain vulnerability, plays a pivotal role in worsening and prolonged pain. We aimed to investigate whether central sensitisation was associated with increased SAPC risk. We also investigated the roles of psychological and pain vulnerabilities, obstetric factors, and analgesic choice in SAPC development.

Methods Our prospective cohort study at KK Women’s and Children’s Hospital, Singapore, included pregnant women aged 21 and above with term pregnancies and American Association of Anesthesiologists (ASA) status II. Psychological and pain vulnerabilities, obstetric factors, and analgesic choice were assessed using established self-reporting scales. Univariate and multivariable logistic regression analyses were conducted. Clinically relevant variables with p-value < 0.10 in univariate logistic regression analyses were selected using a stepwise variable selection to construct the final multivariable model.

Results We recruited 816 postpartum patients between 2017 and 2021, 99 (12.1%) developed SAPC at 6 to 10 weeks postpartum. The multivariable model revealed higher Central Sensitisation Inventory (CSI) score, increased number of pain relief administered, having had artificial rupture of membranes and oxytocic induction, increased blood loss during delivery, having had third degree tear and higher infant’s weight were independently associated with higher SAPC incidence. Having had prostin induction was associated with reduced SAPC risk. The area under the curve of the model is 0.727 (95%CI 0.674-0.780).

Conclusions This study explores SAPC development in psychological and pain vulnerabilities, obstetric factors, and analgesic choice. Further investigations should delve into the underlying mechanisms to develop tailored interventions.