In 1975-79, U.S. women childless at age 30 had low fertility after age 30. Under age- and parity-specific birth rates for 1975-79, such women would average 0.35 first births and 0.6 total births by age 45.
By 1990-95, more women of most educational levels remained childless to age 30, and two distinct patterns of subsequent fertility emerged. Women with college degrees had increased fertility after age 30 due to higher first and second birth rates, higher marriage rates and marital birth rates, and lower marital disruption rates. Women without college degrees experienced no such changes.