Bi-directional associations between maternal and infant sleep, and maternal mental health from late pregnancy to 2 years postpartum.

Evidence on longitudinal bi-directional relationships between sleep and mental health in the perinatal periods is lacking, with infant sleep rarely considered in this relationship. This study analysed data from a randomised controlled trial to investigate the bi-directional relationships between maternal sleep, infant sleep, and maternal depressive and anxiety symptoms, and explored moderators of these associations. A nulliparous community sample (N = 163, Mage = 33.47, SDage = 3.52) self-reported depressive and anxiety symptoms, maternal sleep, and infant sleep over 7 timepoints from 30 weeks' gestation until 2 years postpartum. Data were analysed using cross-lagged panel analyses, controlling for group allocation. Depressive symptoms prospectively predicted maternal insomnia symptoms during late pregnancy. Prospective bi-directional associations between maternal sleep and maternal mood were found across the first 2 years postpartum, and maternal sleep at 6 months showed robust effects on subsequent maternal mood. Concurrently, maternal sleep was correlated with infant sleep, and maternal mood was correlated with maternal (but not infant) sleep. These associations were not moderated by demographic, sleep, or mental health related factors explored. Future studies are needed to examine whether intervening on sleep or mental health may be protective of the other.