Objective Child-related stress following the birth of a child with special health care needs (SHCN) can take a toll on parental health. This study examined how the risk of sick leave due to psychiatric disorders (PD) among mothers of children with SHCN compares with that of mothers of children without SHCN during early motherhood. Methods Responses from 58,532 mothers participating in the Norwegian Mother and Child Cohort Study were linked to national registries and monitored for physician-certified sick leave from the month of their child’s first birthday until the month of their child’s fourth birthday. Results As compared with mothers of children without SHCN, mothers of children with mild and moderate/severe care needs were at substantial risk of a long-term sick leave due to PD in general and due to depression more specifically. Conclusions Extensive childhood care needs are strongly associated with impaired mental health in maternal caregivers during early motherhood.