RESUMO
OBJECTIVE: This study investigated sleep architecture in newborn and six-month-old infants who were born to depressed mothers. METHOD: Sixty-four healthy full-term infants (32 males and 32 females) participated in the study. Of these, 32 were high-risk infants who were born to mothers diagnosed with depression, and 32 were low-risk infants born to mothers without a personal history of depression. 24-hour polysomnography was recorded at zero and six months of age (M0 and M6). Sleep macro-structural parameters (total sleep time, TST; awake time; non-rapid eye movement, NREM sleep (%); rapid eye movement, REM sleep %; arousal index; and sleep efficiency) were analysed at M0 and M6. Micro-architectural sleep features (slow-wave activity, SWA; delta sleep ratio, DSR; spindle density; and rapid eye movement density) were calculated at M6. The data between high-risk and low-risk groups were compared using Student's t-tests. RESULTS: At M0 and M6, the high-risk infants showed more awake time and fewer arousals than the low-risk infants. However, the high-risk group had less NREM% at M0 and a shorter TST as well as less REM% at M6 than the low-risk group. At M6, the high-risk group showed higher SWA, higher DSR and lower spindle density in comparison with the low-risk group. CONCLUSIONS: Altered sleep structure was observed during their first months of life in infants born from depressed mothers, thereby suggesting that the prenatal environment could enhance the depression vulnerability of the child and potentially decrease their neuroplasticity.