The most important time in a child's life to learn and grow is from birth to around five years old when they enter elementary school. Speech, motor skills and critical thinking are all developed during this time period. Children who spend time with their mothers instead of at a day care are much more mentally developed than children in opposite situations. If it is economically feasible, it makes much more sense for a mother to stay home with a child then return to the workforce.
The first few weeks of a baby's life are a critical time for emotional bonding between mother and child. Most mothers are also physically drained in the time following childbirth. If it is at all possible, it is of great importance to both mom and baby to be home together in the first few weeks.
Babies need their mothers as a source of nourishment, comfort and growth. Humans should not separate them unnaturally in order to create more workers. That said, every family should be able to choose which parent stays home with their children to care for them, so if the mother wishes to work she should be able to do so.
The time right after giving birth is a very special time for new mothers. Not only is it a period of adjustment, it is a time during which she gets to know and bonds with her new child. Rushing a mother back to work can have a lifelong impact on the relationship between mother and child as well as negatively affect the mental health of both mother and child.