Sarah Francomano, a publicist in Boston, planned to work within a week of her delivery. She miscalculated and went into labor during a business meeting.

Call it the American way of maternity. Eighty percent of pregnant women who work remained on the job until one month or less before their child's birth, according to newly released Census data for 2003. In 1965 that figure was 35 percent.

Most women work until close to their due date for two reasons: They need the income and they want to use their maternity leave after the baby arrives.