Professor Adrianne Frech of the University of Akron and co-author Sarah Damaske of Pennsylvania State University analyzed longitudinal data from 2,540 women who became mothers between 1978 and 1995.
The research revealed the choices women make early in their professional careers can affect their health later in life, the researchers said.
The study found women who returned full time to the workforce shortly after having children reported better mental and physical health -- specifically, greater mobility, more energy and less depression at age 40.
"Work is good for your health, both mentally and physically," Frech said in a statement. "It gives women a sense of purpose, self-efficacy, control and autonomy. They have a place where they are an expert on something, and they're paid a wage."
Frech said one group of women who were least healthy at age 40 were the "persistently unemployed," who were in and out of the workforce, often not by choice, and experience the highs and lows of finding rewarding work only to lose it and start the cycle again.
"Struggling to hold onto a job or being in constant job search mode wears on their health, especially mentally, but also physically," Frech said.
The findings were presented at the American Sociological Association's annual meeting in Denver.