Association of pain, analgesic, psychological, and socioeconomic factors with sub-acute pain after childbirth: A prospective cohort study.

Study objective: To determine if acute postpartum pain, psychological distress, socioeconomic factors, and labor analgesia were associated with sub-acute pain after childbirth (SAPC; pain starting after childbirth and lasting between four weeks to three months).

Design: Prospective cohort study, from pre-conception to post-partum three months. Setting: Singapore's major public maternity institution. Patients: We included women planning to conceive within a year. We excluded women who were pregnant, taking chemotherapy or psychotropic medications, had diabetes mellitus, received assisted fertility interventions or contraception, did not conceive after 12 months, with multiple pregnancies, or who developed obstetric complications. Interventions: None. Measurements: We investigated the relationship between average pain score during the three days after childbirth (primary exposure) and incidence of SAPC at postpartum three months (primary outcome). Secondarily, psychological distress at pre-conception (Beck Depression Inventory (BDI), Edinburgh Postnatal Depression Scale (EPDS), State-Trait Anxiety Inventory (STAI), Perceived Stress Scale (PSS), General Health Questionnaire-12 (GHQ-12), Life Experiences Survey (LES)) and second trimester of pregnancy (BDI, EPDS, STAI, PSS, Pregnancy Experience Scale (PES)) were assessed. Baseline maternal and socioeconomic characteristics, labor analgesia, maternal and neonatal outcomes were also collected accordingly. Main

Results: Of 317 women who met the study criteria, 30 (9.5%) developed SAPC. Higher average pain score during the three days after childbirth (adjusted odds ratio (aOR) 1.46, 95% CI 1.17 to 1.82, p = 0.001), use of meperidine for labor analgesia (aOR 4.23, 95% CI 1.03 to 17.43, p = 0.046), higher pre-conception GHQ-12 score (aOR 1.14, 95% CI 1.03 to 1.27, p = 0.013), and lack of employment with income during pregnancy (aOR 9.62, 95% CI 3.07 to 30.30, p < 0.001) were independently associated with SAPC, with area under the curve (AUC) of 0.837.

Conclusions: Higher acute postpartum pain scores, use of meperidine for labor analgesia, poorer pre-conception general psychological health, and lack of employment with income during pregnancy are associated with SAPC.