The link between parenting and pay has been demonstrated in a study that shows postponing motherhood leads to an increase in women’s earnings of 9% per year of delay, according to Amalia R. Miller of the University of Virginia. As you might expect, the wage advantage was largest for college-educated women who have the potential to climb the corporate ladder before career interruptions hit.

The study found that motherhood delay leads to a substantial increase in earnings of 9% per year of delay, an increase in wages of 3%, and an increase in work hours of 6%.