on the job later into their pregnancies (Chamberlain, & Garcia, 1983). In the United States in 1890, working women accounted for 15.8 percent of the female population segment. By 1940 the proportion of working women had risen to 24.5 per cent, and by 1980, it had mushroomed to 51.3 percent (Waite, 1981). In 1989, the proportion exceeded 60 percent (United States Department of Commerce, 1990). This growth is illustra ted in Figure 2, which may be found on the following page. The most significant growth occurred between 1940 and 1960 from 24.5 percent to 38 percent, and between 1960 and 1980 from 38 percent to 50.6 percent (Felmlee, 1984). In 1976, as an exam eple, the increase in the
...