The rate of first births among women aged 35-39 years went up 424% from 1970 to 2012, while the first-birth rate for women aged 40-44 years rose 475%, the National Center for Health Statistics reported.
The first-birth rate for women aged 35-39 years was 11.0 per 1,000 women in that age group in 2012, compared with 2.1 per 1,000 in 1970. For women aged 40-49 years, the rate of first births was 2.3 per 1,000 in 2012, compared with 0.4 in 1970, according to the NCHS.
The investigators noted that first-birth rates for women aged 30-34 years "have increased but not as steadily since the early 2000s," and that rates for women under 30 years old "have declined in the past decade."
From 1990 to 2012, first-birth rates in both age groups increased for all races/ethnicities. Among 35- to 39-year-old women, non-Hispanic blacks had the largest increase, while Asian/Pacific Islanders had the largest increase for those aged 40-44 years. American Indian/Alaska native women had the smallest increases in both age groups, the report showed.
The NCHS analysis was based on data from the National Vital Statistics System’s Natality Data File, which includes information for all births in the United States.
