Eleusis - what I am trying to illustrate is that I don't believe (on the basis of all I have read, heard, seen) that a mother's exclusive biological role in childbearing is over the minute she has given birth.
I believe that pregnancy, child birth, breastfeeding form part of a continuum where the mother is the best primary carer, and that a baby, given the chance, separates in a natural, untraumatic way from its mother during its first years until it learns to talk sufficiently well that it can be understood by the outside world beyond its immediate family, and can join in with a group of its peers (with adult supervision) for short periods that increase over time until it becomes an independent adult.
I believe that early return to paid work by mothers interferes with this natural process and causes stress and trauma to many children (and mothers) that has expensive repercussions for individuals and society.
I certainly don't blame mothers for that early return to paid work - it is, by and large, NOT their fault, just a survival response to deeply misguided social policy and cultural environment.
I do believe that a properly progressive society would ensure that women retain proper economic security and the ability to return to work in a job suited to her skills and abilities once her child(ren) had attained a sufficient degree of indendence to be safely placed in a group setting outside the home.