The association between sleep trajectories throughout pregnancy and postpartum pain in individuals with overweight or obesity: A prospective cohort study

Background : Pain after childbirth impacts maternal and infant outcomes. While sleep affects pain in adult populations, research during the perinatal period is limited. This study examines the association between sleep quality and duration before delivery and throughout pregnancy with pain during postpartum hospitalization. Methods : This analysis included 118 pregnant individuals with a pre-pregnancy BMI ≥ 25 kg/m 2 . Group-based trajectory models identified patterns of self-reported sleep quality and duration at six prenatal visits. Pain was assessed every 8 h during the three-day postpartum hospitalization using a 0–10 numeric rating scale. The Area Under the Curve (AUC) for these assessments reflects cumulative pain burden; log-transformed AUC, exponentiated for interpretation. Linear regression analyzed the relationship between sleep (trajectories and before pregnancy) and cumulative pain burden. Results : Two trajectories for sleep quality and two for sleep duration were identified. The “Consistently poor” group showed increasing PSQI scores from 9 to 11, while the “Late worsening” group's scores increased from 4 to 6. The “Late decreasing” duration group consistently slept 6–7 h, while the “Consistently short” group maintained 5–6 h nightly. No statistically significant associations were found between sleep quality (expβ = 0.70, 95% CI: 0.45 to 1.10) or sleep duration trajectories (expβ = 0.68, 95% CI: 0.41 to 1.13) throughout pregnancy and cumulative pain burden. Conclusions : Sleep quality and duration changes during pregnancy were not associated with postpartum pain in this cohort. Future research should explore sleep's impact on pain later in the postpartum period when chronic pain may develop. • Sleep patterns across pregnancy studied in individuals with overweight/obesity. • Postpartum pain was measured repeatedly during hospitalization for recovery insight. • Sleep quality and duration did not predict acute postpartum pain burden. • Results emphasize the need to study sleep and pain links later in postpartum recovery. • Findings highlight the importance of publishing null results in maternal health.