The benefits of going back to work all depend on the mother, the house, the family and the baby, as well as of course, the finances.
Many women do not have the option to not go back to work. Many of them end up feeling overwhelmed and anxious in the work place as they long to be at home. Other mothers have the option of staying home and then end up overwhelmed by the lack of schedule or socializing that the work place afforded them. The people who are most likely not to go back to work are the very wealthy or the very poor. Working as a stay at home mom is hard work, you never actually have a break, or a sick day, or for that matter, external validation, like a pay check.
So, stay at home moms end up feeling ignored and worthless sometimes, when in actuality, it is an art to coordinate alone all that is needed to be done for one household.
At the same time, for many mothers, it simply does not fit with their personality structure to stay at home. When we analyze it on the extrovert introvert spectrum and for their sense of self, for their sanity, they need work. And once they are working, they feel better. Mental health and work outside the home are strongly correlated, for several reasons. There is an embedded structure in the work day and an embedded community in the work force that fosters mental health and clarity.
Sandberg in her pivotal book, Lean In, calls staying at home off ramping and going back into the outside work force as on ramping.
A boss I had once at a clinic I worked at was amazing with this. She off ramped for 10 years. And then when she went back into social work, she immediately was hired as a director for the work she had done ten years ago. Not all mothers have this option, because some occupations are the type where you need to stay on the ball, but many actually are not effected by a decade of absence. The primary question is does it fit your needs to work outside of the home or to stay at home?