How do infant feeding method, sleeping location, and postpartum depression interact with maternal sleep quality?

New mothers generally experience poor and/or disrupted sleep. A range of infant care and mental health factors may impact new mothers' sleep quality. A cross-sectional online survey was completed by a sample of 101 Australian new mothers with children under 12 months (M = 5.52 months, SD = 3.29 months) to examine the relationship between infant feeding method, infant sleeping location, and postpartum depression with maternal sleep quality. Subjective maternal sleep quality was measured using the Pittsburgh Sleep Quality Index (PSQI), and postpartum depression was measured using the Edinburgh Postpartum Depression Scale (EPDS). Overall, new mothers experienced poor subjective sleep quality, with high average PSQI scores, above the cut-off of 5 (M = 9.63, SD = 4.07). The majority of new mothers did not experience postpartum depression, with an average EPDS score below the cut-off of 11 (8.66, SD = 5.20). Mothers who breastfed their infants experienced significantly better subjective sleep quality than mothers who bottle-fed, with a medium effect size (ηp2 = 0.458). Subjective maternal sleep quality did not differ based on infant sleeping location. Poor subjective maternal sleep quality was a significant predictor of postpartum depression. While poor sleep was common in this sample of Australian new mothers, this study demonstrated that new mothers who breastfeed may experience slightly better subjective sleep quality than other feeding methods. Further research into, and better services for the education and advocation of, new mothers' sleep quality will be beneficial to both new mothers and clinicians.