The 36-year-old royal is set to take part in sporadic engagements during October and through to the end of the year, and will return to her full schedule in January.
Ahead of Prince Louis' royal arrival, Peter Fonagy, head of the Anna Freud National Centre for Children and Families, told PEOPLE: "Kate feels it's an incredible privilege to be a mum."
“She’s very keen on children and keen that they should be happy,” added Fonagy, who has worked alongside Kate with her mental health advocacy through the Heads Together initiative.
“Part of her interest in prevention is to make sure that she does things right in her own parenting.”
“She’s genuinely interested in how to make children’s lives better — and what parents and professionals can do to positively influence the lives of children,” he added.