THURSDAY, Aug. 11, 2011 (HealthDay News) -- American women born in 1935 had a higher average number of children than those born in 1910 or 1960, according to researchers who analyzed childbearing differences among three generations of women.
Women born in 1935 had an average of three children per woman, compared with an average of 2.4 for those born in 1910 and two for those born in 1960, their study found.
Of the three generations, women born in 1910 were most likely to be childless by age 50 (19.7 percent), compared with 15.6 percent of women born in 1960 and 11.4 percent of those born in 1935, said the researchers at the National Center for Health Statistics, part of the U.S. Centers for Disease Control and Prevention.
Social and historical factors are a major reason for the childbearing differences between the three generations, the researchers said.
Childbearing by women born in 1910 was affected by the Great Depression and World War II, events which caused high levels of uncertainty about the future and a decrease in marriages linked largely to the lack of employment opportunities for men. In contrast, women born in 1935 began their childbearing years after World War II, when the economy prospered and there was a jump in the number of marriages.
Women born in 1960 had reliable methods of birth control and increased educational and work opportunities -- factors that might explain why they had fewer children, the researchers noted.
The analysis of data from the National Vital Statistics System also showed that women born in 1935 were most likely to have four or more children (37 percent), those born in 1960 were most likely to have two children (35 percent), and those born in 1910 were equally likely to have no, one or two children (about 22 percent each).
Nearly three-quarters of the women born in 1910 and 1935 had their first child by the age of 25, compared with one-half of those born in 1960. The average age when they had their first child was 21 for women born in 1910 and 1935 and 23 for those born in 1960.
Less than 10 percent of women born in 1910 and 1935 had their first child after age 30, compared with nearly 20 percent of those born in 1960.
Women born in 1935 had the lowest average age at first birth (20.8 years), compared with 21.1 for those born in 1910 and 22.7 for those born in 1960.
Two reports on these childbearing patterns were published Aug. 11 by the CDC's National Center for Health Statistics.
The U.S. National Institute of Health and Human Services has more about pregnancy.