Association of maternal hemoglobin levels during pregnancy with sleep and developmental problems in 1-year-old infants: A cohort study.

Background And Aims: Maternal hemoglobin concentration during pregnancy is reported to be associated with various perinatal outcomes and may also be associated with infant development. This study aims to investigate the association between maternal hemoglobin levels during early or mid-pregnancy and sleep and developmental problems in 1-year-old infants.

Methods: We used the data of 66,935 pregnant women who were participants of the Japan Environment and Children's Study, a nationwide cohort study in Japan, between 2011 and 2014.