U.S. Birthrates For Women Under Age 30 Fell To Record Lows In 2019

There has never been a time in U.S. history when women in all age ranges under the age of thirty were less likely to give birth. The birth rate is now highest for women aged 30-34, although this rate too is low by historical standards. The absolute number of births has not been this low since 1985 (despite significant population growth since then).

The decline has been quite dramatic and continues to be particular rapid for teens. While the provisional statistics don't show it, from prior years statistics we can safely predict that the decline has been particularly dramatic for black and Hispanic teens, even though for women in their 20s and early 30s birth rates have been falling faster for white and Asian-American women than for black and Hispanic women.

Meanwhile, birth rates have continued to gradually increase for women aged 35-44. This is partially due to women postponing child bearing to obtain educations and pursue careers, and is partially because fertility treatments have made this possible.

Birth rates have been essentially unchanged for girls aged 10-14 (at a record or near record low reached in 2015), and women aged 45 and older (which are at historically high levels, but still very low).

We can also safely predict that this is due almost entirely to reduced pregnancy rates and not due to increased abortion rates. The abortion rate per pregnancy has remained fairly constant, or has declined, in all recent years, and thus, the U.S. has also approached record low post-Roe v. Wade abortion rates.

To maintain a constant population, the U.S. needs to admit approximately one immigrant per four children born each year.

The provisional number of births for the United States in 2019 was 3,745,540, down 1% from the number in 2018 (3,791,712). This is the fifth year that the number of births has declined after the increase in 2014, down an average of 1% per year, and the lowest number of births since 1985. 

The provisional general fertility rate (GFR) for the United States in 2019 was 58.2 births per 1,000 females aged 15–44, down 2% from the rate in 2018 (59.1), another record low for the nation. From 2014 to 2019, the GFR declined by an average of 2% per year. . . .  

The provisional total fertility rate (TFR) for the United States in 2019 was 1,705.0 births per 1,000 women, down 1% from the rate in 2018 (1,729.5), another record low for the nation. The TFR estimates the number of births that a hypothetical group of 1,000 women would have over their lifetimes, based on the age specific birth rate in a given year. The TFR in 2019 was again below replacement—the level at which a given generation can exactly replace itself (2,100 births per 1,000 women). The rate has generally been below replacement since 1971 and consistently below replacement since 2007.  

… 

The birth rate for teenagers in 2019 was 16.6 births per 1,000 females aged 15–19, down 5% from 2018 (17.4), reaching another record low for this age group. The rate has declined by 60% since 2007 (41.5), the most recent period of continued decline, and 73% since 1991, the most recent peak. The rate had declined an average of 8% annually from 2007 to 2018. . . . The birth rates for teenagers aged 15–17 and 18–19 in 2019 were 6.7 and 31.1 births per 1,000 females, respectively, down by 7% and 4% from 2018, again reaching record lows for both groups. From 2007 to 2018, the rates for teenagers aged 15–17 and 18–19 declined by 10% and 7% per year, respectively. 

The birth rate for females aged 10–14 was 0.2 births per 1,000 in 2019, unchanged since 2015.

The birth rate for women aged 20–24 in 2019 was 66.6 births per 1,000 women, down 2% from 2018 (68.0), reaching yet another record low for this age group. This rate has declined by 37% since 2007. The number of births to women in their early 20s fell by 3% from 2018 to 2019.

The birth rate for women aged 25–29 was 93.7 births per 1,000 women, down 2% from 2018 (95.3), reaching another record low for this age group. The number of births to women in their late 20s declined 2% from 2018 to 2019.

The birth rate for women aged 30–34 in 2018 was 98.3 births per 1,000 women, down 1% from 2018 (99.7). The number of births to women in their early 30s was essentially unchanged from 2018 to 2019. 

The birth rate for women aged 35–39 was 52.7 births per 1,000 women, similar to the 2018 rate of 52.6. The number of births to women in their late 30s increased by 1% from 2018 to 2019.  

The birth rate for women aged 40–44 in 2019 was 12.0 births per 1,000 women, up 2% from 2018 (11.8). The rate for this age group has risen almost continuously since 1985 by an average of 3% per year. The number of births to these women increased by 2% from 2018 to 2019.  

The birth rate for women aged 45–49 (which includes births to women aged 50 and over) was 0.9 births per 1,000 women, unchanged since 2015. The number of births to women in this age group was also essentially unchanged from 2018 to 2019.

From here. 

Historical Birth Rates In North American and the World

Birth rates records are not comprehensive back all of the way to Colonial era, and mostly don't exist at all in Pre-Columbian times.

But, in all of world history prior to the 19th century, birth rates for women aged 15-29 were higher than they are today in virtually all cultures, except for subcultures of nuns and pagan vestal virgin priestesses. The technologies that facilitate reducing births per woman, the economic forces that encourage that approach didn't exist until more recent times, and high child mortality rates made having many children a necessity to prevent population collapse.

There were cultural differences within these parameters, however. With regard to the regional and cultural differences, as I noted in an October 6, 2012 post at this blog:

The differences in adolescent sexuality and family structure we see in "Red State/Blue State" comparisons in the past decade were deeply ingrained already in colonial New England, Pennsylvania, Appalachia and Virginia by the 1770s and have clear British antecedents which have faded to near irrelevance to some extent where they originated. By then, 10% of women in the Delaware Valley (New Jersey, Pennsylvania, Delaware and Northern Maryland), 15% of New England women, 30% of women in Virginia and 40% or more of women in Appalachia (one contemporaneous source put the figure as high as 94% in one county) were pregnant when they married. 

On that wedding day, the average Delaware Valley woman was 24, the average New England woman was 23 years old, the average Virginia woman was 18, and the average Appalachian woman was 19. 

About 33% of the Delaware Valley women were literate, as were 50% of the New England women, 25% of the Virginia women, and a smaller percentage of the Appalachian women.

The average age of women at first marriage in the U.S. today is 28 years old. 

The regional differences between different early American subcultures probable had its roots in differences in child mortality rates historically in those cultures. Child mortality was probably higher in Appalachia and Virginia than it was in the Delaware Valley and New England in the 1770s.

Of course, these averages also conceal a considerable age spread even in the Delaware Valley and New England where the average age of first marriage was relatively high and relatively few women were pregnant when the got married. Far more women would have had children at a young age than do so today, even though teenage marriage and child bearing wasn't as common in pre-modern times as often assumed.

From the U.S. Census Bureau. See also here.

Thus, for a full century of the time period in which we have data, from 1890 to 1980, the median age for women at their first marriage in the U.S. as a whole was between 20 and 22. 

The increase in the age of women at their first marriage since 1950s coincides with increasing percentages of women going to and completing college, and also to graduate and professional schools. Men are also much more likely to go to college (although women are now significantly more likely to be college graduates than men).

The percentage of law school students who were women didn't exceed 4.1% until 1965 when it hit 4.3% and increased steady thereafter (after having been between 2.8% and 4.1% from 1947 to 1964) and has been in excess of 50% since 2016.

The increasing age of marriage is a global trend, worldwide: "The average age of marriage for women increased from 21.8 to 24.7 years from the seventies to the mid 2000s, with the average age for men rising a comparable amount."

The average age gap was about four years in 1890, narrowed slightly during the Great Depression, was back to four years after World War II ended, to about 2.5 years in the 1960s, and has held stead at about two years since 1980. As countries grow richer, the difference in marrying age tends to narrow (the gap is about 5 years in Egypt but only 1.6 years in France and only 1.4 years in Japan); quite a bit of this difference is driven by younger ages of marriage for women ("According to U.N. reports, 39 countries have data showing that 20% of women married by age 18. In twenty countries, a full 10% of women married by age 15. In only 2 countries, however, are 10% of men married before the age of 18.").

The marriage age trends are more consistently higher now than they were in the late colonial era in the U.S., with the state with the lowest average age matching the Delaware Valley high at that time. But, women in New England and the Delaware Valley now marry about three years later than Appalachia (compared to a gap of five to six years in the colonial era), although the gap between these regions and Virginia is now just one or two years, instead of four or five years in the colonial era. 

The U.S. state with the lowest median first marriage age is, unsurprisingly given its predominantly Mormon religious affiliation, Utah at 24.2 years old for women and 26.2 years old for men, with Idaho which is also heavily Mormon as a runner up with 25.1 years old for women and 26.7 years old for men. The oldest average age of first marriage in a U.S. state is in Massachusetts, where the median age of first marriage for women is 29.7 and for men is 30.9 years. The District of Columbia has the highest median age of marriage for women, at about 30, which is also about the median age of first marriage for men (in part, this is because it has the lowest percentage of the population ever married, mostly because a large percentage of the D.C. population is African-American than in any U.S. state or in Puerto Rica, since the African-American marriage rate is much lower than the marriage rate for other races designated by the Census bureau, a trend that has emerged in the post-Civil Rights era).

The District of Columbia is the only place in the U.S. without a significant age gap between median age of first marriage for men and for women. The gap is about two year in most of the U.S. but closer to one year in the Northeast (where median ages at first marriage tend to be on the high side). The age gap is about twice as large (3.0 years v. 1.5 years) in couples where both are foreign born v. those where both were born in the U.S.; there is a similar gap for high school dropouts v. high school graduates (3.1 years v. 1.6 years) some of which is due to non-native born people making up a disproportionate share of high school dropouts.

Data from 2005 to 2009 show basically same regional trends with slightly lower actually ages (Puerto Rico is in the mid-range at 38th oldest):

The U.S. Census Bureau keeps track of when Americans get hitched. Here is the median age at first marriage for women in all 50 states, Puerto Rico and Washington, D.C. as of 2005-2009: 

1. Idaho: 23.2
2. Utah: 23.3
3. Wyoming: 24.2
4. Arkansas: 24.3
5. Oklahoma: 24.4
6. Kentucky: 24.8
7. West Virginia: 25.0
8. Kansas: 25.0
9. Tennessee: 25.2
10. Texas: 25.2
11. Alaska: 25.2
12. North Dakota: 25.3
13. Alabama: 25.3
14. Iowa: 25.4
15. Nebraska: 25.4
16. Missouri: 25.6
17. Nevada: 25.6
18. South Dakota: 25.6
19. North Carolina: 25.7
20. Montana: 25.7
21. Colorado: 25.7
22. Indiana: 25.7
23. Mississippi: 25.8
24. Arizona: 25.8
25. New Mexico: 25.8
26. Louisiana: 25.9
27. Washington: 25.9
28. Georgia: 25.9
29. Oregon: 26.0
30. Minnesota: 26.3
31. Wisconsin: 26.3
32. Ohio: 26.3
33. Maine: 26.4
34. South Carolina: 26.4
35. Florida: 26.4
36. Michigan: 26.4
37: Virginia: 26.4
38: Puerto Rico: 26.5
39. Delaware: 26.6
40. New Hampshire: 26.8
41. California: 26.8
42. Hawaii: 26.9
43. Vermont: 26.9
44. Illinois: 27.0
45. Pennsylvania: 27.1
46. Maryland: 27.3
47. Connecticut: 27.6
48. New Jersey: 27.7
49. Rhode Island: 28.2
50. New York: 28.4
51. Massachusetts: 28.5
52. District of Columbia: 29.7

Marriages tend to be at a younger age where Mormon (and to a lesser extent Evangelical Christian) religious affiliation is more common, and in rural areas.

The percentage of women enrolled in law school tracks median age of women at first marriage rather closely (although not perfectly):

The methodology used by the Census Bureau to compute marriage ages changed in 1990. 

Historical American Total Fertility Rates

There were high pre-industrial levels of total lifetime fertility for married women (i.e. typically more than six children per lifetime for women who lived for all of their child bearing years) in Colonial and Pre-Columbian times, although this had abated by the time of the Great Depression.

From Statistica.com citing Aaron O'Neill, "Total fertility rate of the United States 1800-2020" (January 22, 2020).

The U.S. total fertility rate fell below the replacement rate briefly around 1940 and again in the early 1970s.

These birth rates exceed those of pre-modern societies discussed below, and gave rise to rapid natural increase (i.e. excess of births over deaths without regard to immigration) in the total population.

We also have decent data on pre-1790 total fertility rates in Europe, where total fertility rates ranged from 4.5 to 6.2, with mean ages at first marriage of 25-26 years old for women (suggesting that women in that era had on average, 2.5 to 4.2 children who died before having children of their own). 

Colonial era American women married earlier than their European counterparts, and population growth was greater in North America (even apart from massive amounts of immigration) than it was in Europe, so Colonial era American women very likely had more children per lifetime than their European counterparts of the same era, with a total fertility rate that was probably more than 7, and birth rates of more than 250 per 1000 women of child bearing age.

Pre-Colombian Birth Rates In North America

Birth rates at a given age were probably as high as they were in 1800 in Colonial populations among Pre-Columbian North Americans, if not higher. At that time, life expectancies for women were lower (about 23 years at birth and about 20 years at age 15), and that reduced the total fertility rate. See, e.g. Pre-Columbian North America can be found in S. Ryan Johansson, "The Demographic History of the Native Peoples of NorthAmerica: A Selective Bibliography", 25 Yearbook Of Physical Anthropology 133-152 (1982).  

Birth rates inversely track child mortality rates, because people have more kids (and generally overcompensate) when there is a significant risk that some of their children will not live to adulthood, and must do so out of mathematical necessity when the total population size is stable.

Another source surveying pre-modern mortality rates globally and in pre-modern history notes that:

Across the entire historical sample the authors found that on average, 26.9% of newborns died in their first year of life and 46.2% died before they reached adulthood. Two estimates that are easy to remember: Around a quarter died in the first year of life. Around half died as children. What is striking about the historical estimates is how similar the mortality rates for children were across this very wide range of 43 historical cultures. Whether in Ancient Rome; Ancient Greece; the pre-Columbian Americas; Medieval Japan or Medieval England; the European Renaissance; or Imperial China: Every fourth newborn died in the first year of life. One out of two died in childhood. . . . 

There is another piece of evidence to consider that suggests the mortality of children was in fact very high in much of humanity’s history: birth rates were high, but population growth was close to zero.

The fertility rate was commonly higher than 6 children per woman on average, as we discuss here. A fertility rate of 4 children per woman would imply a doubling of the population size each generation; a rate of 6 children per woman would imply a tripling from one generation to the next. But instead population barely increased: From 10,000 BCE to 1700 the world population grew by only 0.04% annually. A high number of births without a rapid increase of the population can only be explained by one sad reality: a high share of children died before they could have had children themselves.

Estimates of infant mortality rates in the Pre-Columbian agricultural Inca and Aztec societies (from a chart in the article quoted above) ranged from 27% to 35% of children who were born. Estimates of all deaths before age 15, in those societies, ranged from 48% to 53% of children who were born, well in line with estimates from other pre-modern societies with similar levels of technology.

This implies that a woman who lived long enough to have children had to have at least four children per lifetime, on average, to prevent population decline, and those children had to be squeezed into what was, on average, a shorter than modern reproductive lifespan, because more women died before menopause in pre-modern times. Directly measured total fertility rate data suggests that these child mortality rates were actually underestimates, because total fertility rates were probably higher than four children per woman per lifetime.

The birth rate for women aged 15-35 would have had to be about 200 per 1,000 women in that age range to prevent the population from declining (and we known that, in the long run, ancient populations were stable or increasing). 

This is about double the birth rate of modern American women aged 30-34 who have the highest birth rate of modern American women of any age, and birth rates in the U.S. are higher than those in most other developed countries.

International Comparisons

The U.S. is still far from the bottom in total fertility rate of 1.7. The world average total fertility rate is 2.4 which isn't far above the replacement rate of 2.1, and 90 out of 200 sovereign states and dependencies are below the replacement rate. 

The World Bank estimate of 2018 puts the U.S. at 145th, out of 185 sovereign states and 15 separately listed dependencies (Puerto Rico, however, is in 199th place at 1.0). There are 55 other countries or dependencies have lower total fertility rates. 

Total fertility rates via Wikipedia (the map reflects some rounding).

Today, Africa, the Middle East, Afghanistan, Pakistan and Oceania are predominant among countries with high total fertility rates. 

Niger at 6.9 is at the top, at about the same total fertility rate as the United States in the year 1800. 

Somalia is the runner up at 6.1, at about the same total fertility rate as the United States in the year 1840. 

Afghanistan at 4.5 is the highest out of Africa, followed by the Solomon Islands at 4.4 which is the highest in Oceania, at about the same total fertility rate as the United States in the year 1890.

Yemen at 3.8 is the highest in the Middle East, at about the same total fertility rate as the United States in the year 1900.

Pakistan is the highest in South Asia at 3.5, at about the same total fertility rate as the United States in the year 1915 and again at the peak of the Baby Boom in the U.S. in 1960.

India is at 2.2 (with immense regional variation within the country), at about the same total fertility rate as the United States in the years 1933, 1944 and 1972.

Bangladesh, Bhutan, Vietnam and Malaysia are at 2.0, at about the same total fertility rate as the United States in the year 1975.

France at 1.9 is the highest in Europe, at about the same total fertility rate as the United States in the year 2015.

China, Australia, Denmark, New Zealand, and the U.K. at 1.7 are about the same as the U.S. today.

Russia, Germand and the Netherlands are at 1.6. 

Thailand, Switzerland and Canada are at 1.5. 

Japan is at 1.4. 

Italy and Spain are at 1.3. 

South Korea at 1.0 is at the bottom.