When I have had moms go on mat leave they have always kept the children full time for the first three months to get past the sleep deprived newborn stage and then drop the older kid down to part time (3 days a week) for the rest of mat leave. I would not hold a spot or two for a year if I could fill it with a full time child .... I have two moms on mat leave right now .... One just start last week and she is keeping the older child in full time however she has said that doesn't mean she will bring him everyday but the spot is hers to use. The other one is 2/3 of the way through and is down to part time and can only use the same three days she chose.