According to the U.S. Census Bureau, women are working later into their pregnancies.

Seventy-six percent of women are on the job one month or less before giving birth.

That's more than double what it was in the 1960s.

New mothers are also taking shorter maternity leaves, with 55 percent of moms back at work within six months.

That's compared to 14 percent 40 years ago.

"Partly this is about economics, " Carol Evans of Working Mother Magazine said.  "Working mothers are really earning a huge part of the household income today."

Still, t's not only about the money.

It was found that a quarter of first-time moms are over 30 and say they are set in their careers.