Live Births in the United States, 1909-2019
Total number of births in the United States from 1909 to 2019 and number of births by age group of mother from 1968 to 2019 are quantified and discussed.
Table of Contents
Introduction
While the analysis of reproductive responsibility in the United States done herein is primarily based on estimates from the National Survey of Family Growth (NSFG), the number of live births in the United States is known from the National Vital Statistics System (NVSS) of the National Center for Health Statistics (NCHS), which aggregates, at the federal level, birth certificate data collected by the several states of the United States.
As discussed and graphed previously, NSFG estimates of live births are generally consistent with the counting done by the NVSS. Nonetheless, the NVSS counts are more accurate and ought to be used whenever possible.
Data Sources
The NVSS makes detailed public use data files available for birth data from 1968 on. These public use data files are converted to more readily usable formats by the National Bureau of Economic Research. These converted data files were the source for the number of births in the United States in the plots below from 1968 on.
For births from 1909 to 1967, data were taken from “Births and General Fertility Rates: United States” data set used for the NCHS Data Visualization Gallery. While there is an accompanying “Percent Distribution of Births for Females by Age Group: United States” data set, the resolution of these percentages is only to the tens of percents, making it useless for estimating births by age group. Therefore, Figure 2 below only plots live births by age group for 1968 on, unlike Figure 1 which plots total live births in the United States from 1909 on.
Results
Figure 1: Total number of live births in the United States. Estimates left of the dashed line are based on summary statistics, whereas estimates right of the dashed line are calculated from detailed vital statistics public use data files. Source: National Center for Health Statistics.
Figure 1 illustrates that there was a dramatic increase in live births in the United States in period following World War II during the so-called “baby boom.” The total number of live births never decreased back to pre-war levels, instead fluctuating in the range of 3.25 to 4.25 million births per year. Total births per year peaked in 1957 and again in 2007.
Figure 2: Number of live births in United States by age group of mother. Source: National Center for Health Statistics.
Figure 2 gives more insight in the demographics of new mothers in the United States since 1968. Generally, there has been a declining number of births to younger mothers, and an increasing number of births to older mothers.
For both teens aged 15 to 19 years old and young women aged 20 to 24 years old, there was a peak in the number of births per year in 1970. With some fluctuations, the number of births among these age groups has been on a decreasing trend since then.
On the contrary, the number of births to women aged 30 to 34 years old had a local minimum in 1973 and has, with some fluctuations, been on an increasing trend since then. Similarly, the number of births to women aged 35 to 39 years old had a local minimum in 1975 and has been on an increasing trend since then. Even births to women aged 40 to 44 years old, which have historically made up a very small proportion of births, has had an increasing trend since the 1980s.
Births to women in the 25 to 29 years old age group have fluctuated over this time period, but have not been on a clear increasing or decreasing trend since 1968.
