Sleep and fatigue complaints during pregnancy versus perinatal depression: Impact on toddler cognition

Sleep and fatigue complaints during pregnancy may increase risk for cognitive impairment among offspring, yet this relationship is difficult to disentangle from related risk factors such as perinatal depression. This longitudinal study examined the role of prenatal sleep/fatigue disturbances, independent of pre- and postnatal depression, and offspring cognition at age 24-36 months in relation with the gestational timing of sleep/fatigue disturbances.

Participants included 127 mother-child dyads. Maternal sleep (i.e., difficulties falling/staying sleep or sleeping too much), fatigue, and depression were self-reported monthly via the Patient Health Questionnaire-9 (PHQ-9) across the second and third trimesters. The Bayley Scales of Infant Development-4 cognition subscale was administered at 24-36 months. Hypothesis-driven and data-driven (fuzzy c-mean clustering) analyses assessed relationships between prenatal sleep/fatigue, separately by trimester, and toddler cognition after accounting for pre- and postnatal depression symptoms and prenatal medications.

Maternal sleep and fatigue disturbances in the second, but not third, trimester were associated with poorer offspring cognition at 24-36 months (β = -0.24, p = 0.038). Fuzzy c-mean clustering analysis of PHQ-9 data returned a 7-profile solution characterizing depressive symptom clusters. A cluster profile defined by high sleep/fatigue complaints and low mood symptoms in the second trimester was associated with lower offspring cognition at 24-36 months (β = -1.39, p = 0.028).

Maternal sleep and fatigue disturbances during the second trimester were associated with poorer toddler cognition. Further studies should assess maternal biological mechanisms (e.g., stress, cortisol, oxygenation, inflammation, immunity modulation) as well as the impact of clinical sleep interventions in pregnancy on cognitive development of offspring.