So women these days are more likely to work during pregnancy, says the U.S. Census Bureau. As someone who grew up in a time when working while knocked up is so common, I’m tempted to say “duh.” But my inner historian knows well, and appreciates, that this hasn’t long been the case. And here are the facts, courtesy of the Council on Contemporary Families:

Two-thirds of women who had their first child between 2001 and 2003 worked during their pregnancy compared with just 44 percent who gave birth for the first time between 1961 and 1965, according to a report released today by the U.S. Census Bureau.

The report, Maternity Leave and Employment Patterns: 1961–2003, analyzes trends in women’s work experience before their first child, identifies their maternity leave arrangements before and after the birth and examines how rapidly they returned to work.

Women are more likely to work while pregnant than they were in the 1960s, and they are working later into their pregnancies. Eighty percent who worked while pregnant from 2001 to 2003 worked one month or less before their child’s birth compared with 35 percent who did so in 1961-1965.

Women are also returning to work more rapidly after having their first child. In the early 1960s, 14 percent of all mothers with newborns were working six months later, increasing to 17 percent within a year. By 2000-2002, the corresponding percentages had risen to 55 percent and 64 percent. (The period of analysis is restricted to women who gave birth by 2002 because some who gave birth in 2003 did not have one full year of employment data by the time of the interview in 2004.)

Other highlights:

— In 2001-2003, 49 percent of first-time mothers who worked during pregnancy used paid leave before or after their child’s birth, while 39 percent used unpaid leave. Twenty-five percent quit their jobs: 17 percent while they were pregnant and another 8 percent by 12 weeks after the child’s birth.

— Forty-three percent of women in 2001-2003 used paid leave after their child’s birth compared with 22 percent before their child’s birth.

— Sixty percent of mothers with a bachelor’s degree or more received paid leave benefits compared with 39 percent of mothers with a high school diploma and 22 percent of those who had less than a high school education.

— Eighty-three percent of mothers who worked during pregnancy and returned to work within a year of their child’s birth returned to the same employer. Seven in 10 of these women returned to jobs at the same pay, skill level and hours worked per week.

Hmmm. Very interesting.