Tag Archives: births

Fertility trends explained, 2017 edition

Not really, but some thoughts and a bunch of figures on the 2017 fertility situation.

There was a big drop in the U.S. fertility rate in 2017. As measured by the total fertility rate (TFR), which is a projection of lifetime births for the average woman based on one year’s data, the drop was 3.1%, from 1.82 projected births per woman to 1.76. (See this measure explained, and learn how to calculate it yourself, in my blockbuster video, “Total Fertility Rate.”) To put that change in perspective, here is the trend in TFR back to 1940, followed by a plot of the annual changes since 1971:

tfr4017

tfrchanges

That drop in 2017 is the biggest since the last recession started. In fact, we have seen no drop that big that’s not associated with a time of national economic distress, at least since the Baby Boom. In 2010, I noted that the drop in fertility at that time preceded the official start of the recession and the big unemployment spike. There is now some more systematic evidence (pointed out by Karen Benjamin Guzzo) that fertility falls before economic indicators turn down. Which makes this New York Times headline a little funny, “US Births Hit a 30-Year Low, Despite Good Economy.” This is a pretty solid warning sign, although not definitive, of an economic downturn coming in the next year or so. (On the other hand, maybe it’s a Trump effect, as people are just freaking out and not thinking positively about the future; something to think about.)

Whatever the role of immediate economic conditions, the long-term trend is toward later births, which is generally going to mean fewer births — both because people who want later births tend to want fewer births, and because some people run out of time if they start late. And that is not wholly separable from economic factors, of course. People (especially women) delay childbearing to improve their economic situation, as they improve their economic situation when they delay births (if they have the right suite of economic opportunities). To show this trend, I’ve been updating this figure for a few years (you’ll find it, and a description, in my book Enduring Bonds).

change in birthrates by age 1989-2016.xlsx

The real reason I made this figure was to highlight the interconnected nature of teen births. Birth rates for teens have fallen dramatically, but it’s been along with drops among younger women generally, and increases among older women — it’s about delaying births overall. Note, however, that 2017 is the first time since the depths of the last recession that birth rates fell for all age groups except women over age 40.

So, sell stock now. But it is hard to know for sure what’s a local temporal reaction and what’s just the way things are going nowadays. For that it’s useful to compare the U.S. to other countries. The next figure shows the U.S. and 15 other hand-picked countries, from World Bank data. Rising fertility in the decade before the last recession wasn’t so unusual. We are a little like Spain and France in this figure, who had rising fertility then and falling now. But Germany and Japan are still rising, at least through 2016. All this is at below-replacement levels (about 2.0), meaning eventually these rates lead to population decline, in the absence of immigration. The figure really shows the amazing fertility transformation of the last half century, especially in giant countries like China, India, and Brazil. Who would have thought we’d live to see Brazil have lower fertility rates than the U.S.? It’s been that way for more than a decade (click to enlarge).

country fertilitiy trends.xlsx

Anyway, it’s my position that our below-replacement fertility levels are themselves nothing to worry about at present. There are still lots of people who want to move here (or, there were before Trump). And we can live with low fertility for a long time before the population starts to decline in a meaningful way. Eventually it will be a good idea to stop perpetual population growth anyway, so we may as well start working on it. This is better than trying to shape domestic policy to increase birth rates.

That said, there is an argument that Americans are having fewer children than they want to because of our stone age work-family policies, especially poor family leave support and the high costs of good childcare. I’m sure that’s happening to some degree, but it’s still the case that more privileged people, who should be able to overcome those things more readily — people with college degrees and Whites — have lower fertility rates than people who are getting squeezed more. People who assume their kids are going to college are naturally concerned with rising higher education costs, both their own loan payments and their kids’ future payments. So it’s a mixed bag story. Here are the predictors of childbearing for women ages 15-44 in the 2016 American Community Survey. These are the probabilities of having had a birth in the previous 12 months, estimated (with logistic regression) at the mean of all the variables shown.*

birth model simple 2016.xlsx

Interesting that there’s only a small foreign-born fertility edge in this multivariate model. In the unadjusted data, 7.4% of foreign-born versus 6.0% of U.S.-born women had a baby, but that’s mostly accounted for by their age, education, and race/ethnicity.

To summarize: 2017 was a big year for fertility decline (at all but the highest ages), the economy is probably about to tank, and the U.S. fertility rate is still relatively high for our income level, especially for racial-ethnic minorities.

Happy to have your thoughts in the comments. For more, check the fertility tag.


* Here’s the Stata code for the regression analysis. It’s just some simple recodes of the ACS data from IPUMS.org. Start with a file of women ages 15-44, with the variables you see here, and then do this to it:

recode educd (0/61=1) (62/64=2) (65/90=3) (101/116=4), gen(edcat)
label define edlbl 1 "Less than high school"
label define edlbl 2 "High school graduate", add
label define edlbl 3 "Some college", add
label define edlbl 4 "BA or higher", add
label values edcat edlbl
gen raceth=race
replace raceth=4 if race==5 | race==6 /* now 4 is all API */
replace raceth=5 if hispan>0
drop if race>5
label define raceth_lbl 1 "White"
label define raceth_lbl 2 "Black", add
label define raceth_lbl 3 "AIAN", add
label define raceth_lbl 4 "API", add
label define raceth_lbl 5 "Hispanic", add
label values raceth raceth_lbl
egen agecat=cut(age), at(15(5)50)
gen forborn=citizen!=0
gen birth=fertyr==2
logit birth i.agecat i.raceth i.forborn i.edcat i.marst [weight=perwt]
margins i.agecat i.raceth i.forborn i.edcat i.marst

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Is there sex selection among Asian immigrants in the US?

There is a 2008 paper reported in the New York Times in 2009, which found skewed sex ratios among children of immigrants from China, Korea, and India, if their older siblings were girls, using the 2000 Census. The implication was that some parents were using IVF or abortion to select boy children if their first two were girls — as is the case in their home countries. There has been some other research on this from the early 2000s, but I haven’t seen it updated since then.

I took a quick stab at it, but don’t have time right now to pursue it more thoroughly. So here’s the quick answer I got, and I shared my data, code, and results in an Open Science Framework project, here. I hope someone will be interested and pursue it further (using my approach or not). The files there include all different ethnic/racial groups.

This is preliminary.

Using the American Community Survey data from 2010-2015, from IPUMS.org, I took U.S.-born children ages 0-5, whose parents were both born in China, Korea, or India and both were present in the household. I counted the sex of any present siblings under age 15 (excluding step- and adopted children). Then I restricted the data to those with 2 older siblings, and compared the sex ratios among those who had 0 or 1 older sister to those who had 2 older sisters. I did this in a logistic regression controlling for individual years of age, and using ACS person weights. There are judgment calls to make about age, siblings, data and other issues. The older you get the more likely you are to have kids moving out in a way that is not sex-neutral (for example, if parents with girls are more or less likely to divorce), and so on. Should parents be matched on immigration status, siblings born abroad included, why the years 2010-2015, and so on. This is what I mean by preliminary. But these results are interesting enough to prompt me to post them and encourage discussion and more analysis.

Here’s what I got:

sex selection.xlsx

The sex differences between those with 0/1 older sister and 2 older sisters are not statistically significant at p.<.05 in each of the three groups, but they are for the combined set (.046). These comparison involve a few hundred cases. Here are the unweighted, unadjusted results:

sexratiosunweighted

As you can see, just a few families intervening to choose boys — or some other force rearranging the living arrangements, or survival, of children and families, and the difference would not hold. Still, I think it’s worth pursuing. Maybe someone already has. If you decide to get into it, feel free to use this stuff, and let me know what you come up with!

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How do Black-White parents identify their children?

In 2015 the American Community Survey yields an estimate of 66,913 infants who have one Black parent and one White parent present in the household. (Either parent may be multiracial, too.)

What is the race of those infants? 73% of them were identified as both White and Black by whoever filled out the Census form.

bwinfants

(Note “other” doesn’t mean they specified “other,” it just means they used some other combination of races.)

These are children age 0 living with both parents, so it’s a pretty good bet they’re mostly biological parents, though some are presumably adopted. This is based on a sample of 507 such infants. If you pooled some years of ACS there is plenty to study here. Someone may already have done this – feel free to post in the comments.

That’s it, just FYI.

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If the National Marriage Project told you it was going to rain, would you bring an umbrella?

Why do academics and journalists lend legitimacy to the National Marriage Project?

The Centers for Disease Control: You bought that.

The Centers for Disease Control: You bought that.

I today’s New York Times Week in Review, Andrew Cherlin offers this:

Having a child outside of marriage has also become common. According to a report by the National Marriage Project at the University of Virginia, 47 percent of American women who give birth in their 20s are unmarried at the time.

It took me 3 minutes to find the the 2010 report on birth data from the National Center for Health Statistics (NCHS), a branch of the Centers for Disease Control, and another 1/2 minute to locate the table with this information, which is table 15. Because of my weakness in algebra, it took me another 5 minutes to turn the number of babies born to unmarried women in the age range 20-24 (600,833) and in the age range 25-29 (384,865) and the percent unmarried that those represented (63.1% and 33.9%, respectively), into the total births to women in their 20s (2,087,487) and the percentage of all those to unmarried women (47.2%).

The New York Times paid for that statistic through taxes, which its government has provided. So why publish an essay by a sociologist with a named chair crediting the National Marriage Project, a right-wing front run by the discredited Brad Wilcox on behalf of big-money Christian conservatives? (In other news, the Heritage Foundation reported that the unemployment rate in February was 7.7%).

Maybe the media establishment simply doesn’t know a simple government statistic when they see one. But they see the university label and fancy website, and guy with the (implied) elbow patches, and they think the number is more complicated than it looksRather than hire a qualified unpaid intern to check facts and credit them to their actual sources, maybe they just trust the experts they rely on. (This is the David Brooks strategy.)

With resources for journalism and social science research on the decline, and foundation money playing a growing role in providing information to the media, this is predictable – but still lamentable.

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Yes, mothers and fathers still exist

On FamilyScholars.org, which (having retreated on opposing homogamous marriage) is busy promoting its “new conversation on marriage,” Elizabeth Marquardt writes: “Where do babies come from? The state of New York seems unsure.”

Her link to a “report” is to one of those “you wouldn’t believe what my friend saw” posts on the Christian conservative site First Things:

A friend’s wife recently gave birth. He reports that the New York birth certificate asks for the sex of the mother, and the sex of the father.

It goes on to mock people who think seriously about sex and gender. And so the thing starts spreading around the religious-conservative sky-is-falling blogosphere.

shock_horror_3

I’m not too embarrassed to say I spent 15 minutes trying to look this up. Live and learn.

It’s hard to find information about birth certificates, because everything online keeps steering you to ways to order birth certificates, not create them. But, in New York state it appears there is a state system, and a state system excluding New York City. On the New York City site, there is an Electronic Birth Registration System, described here. It asks for a lot of information about the mother and father, but not their sex or gender.

I didn’t find the equivalent for the rest of the state, but the state’s Department of Health reports that they follow National Center of Health Statistics (NCHS) guidelines, which seem to refer to this revised birth certificate recording form, which was revised in 2003. In addition to health information, it records the mother’s and father’s marital status (mother only), country of birth, education, Hispanic origin, and race. The mother is “the woman who gave birth to, or delivered the infant.”

The only mention of sex (or gender) pertains to the child: “Print or type whether the infant is male, female or if the sex of the infant is not yet determined.” And “not yet determined” is a temporary state, as the recording instructions clarify:

An N code for “not yet determined” should not be allowed for any record in the file at the time the file is closed. NCHS will query states to obtain the sex of the infant for all records still retaining the N code at the time the file is closed.

 

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Births to mothers in their forties are less common now than in the old days

In my post the other day I suggested that, when it comes to children’s health, mothers’ health is a bigger issue than mothers’ (advancing) age when they give birth. I was motivated to post it by the widespread discussion of Judith Shulevitz’s essay in the New Republic, “How Older Parenthood Will Upend American Society” — discussion that has continued with today’s On Point (which I haven’t heard yet), including the author Elizabeth Gregory, who has written Ready: Why Women Are Embracing the New Later Motherhood (which I haven’t read yet).

In the comments, several people (Reeve Vannamen and relfal) brought up the issue of later births in the olden days (before 1970). We need to think about two different issues: having first children at a later age, and having any (or many) children at a later age. For some questions of children’s health – especially the sperm-mutation issue with autism – I don’t think it matters: an older-age birth is an older age birth. The same goes for the angst over whether children will know their grandparents, whether parents will be too old to take them to soccer practice, and so on.

On the other hand, “starting a family” at an older age (because, remember, it’s not a “family” until you have kids), is a different issue, with its own implications for total fertility rates, the age composition of the population, etc.

Both having any children and having first children at older ages have been increasing in recent decades, but having any children at older ages is not historically unprecedented. Here are the birth rates for women ages 40-44, from 1940 to 2011, along with the percentage of all children born to those women from 1960-2010:

maternal-age-40-11

Sources: Birth rates 1940-1969, 1970-2010, 2011; Percent of births 1960-1980, 1980-2008.

Birth rates to women ages 40-44 are still substantially lower than they were in the olden days. So the number of kids whose parents will be over 60 when the kids come back to live with them after college is lower now despite an increase for 30 years.

On the other hand, the percentage of kids born to older mothers has surpassed those rates, because these are more often first or second, rather than third or fourth or fifth children. Put another way, the chance that women will have their first, and possibly only, baby at an older age has increased since 1960. While the overall birth rate for older women is still lower than it was in 1960, the first-birth rate is much higher. Here is the birth rate among women with no previous births, for those aged 35, 40 and 45, from 1960 to 2005:

first birth rates 60-05

Source: Table 4 on this page.

In 1960, only 4% of women who reached age 35 without having a baby had one that year. They probably weren’t just delaying their childbearing intentionally or putting off finding a mate while they pursued their careers. On the other hand, by 2005 almost 9% of those who reached age 35 without having a baby had one that year. The late first birth has become much more common.

Now if you go back to the promo blurb for On Point, you see how the issues are jumbled together:

American parents are having kids old and older. Look around. Are those two that child’s parents? Or its grandparents? It is very often hard to know these days. In many ways, this has been liberating. Twenty-somethings with a child-free, diaper-free decade of youth. People with time and space to start careers. But there is a price, and it’s becoming clearer. Older parents juggling kid’s soccer and their own aches and pains. Kids who won’t know their grandparents. Parents who won’t know their grandkids. And a baby bust.

The hardships faced by older parents are nothing new, but parents used to have more kids around when they went through them. It’s good to keep an eye on the issues separately.

Note: there is some more background and analysis in my working paper: here.

 

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Study shows home births are not as safe. So?

There’s an interesting example of how to interpret scientific results — and draw policy implications from them — from the world of birth practices and safety.

The subject of the debate is a major new study from the British Medical Journal. The study followed more than 60,000 women in England with uncomplicated pregnancies, excluding those who had planned caesarean sections and caesarean sections before the start of labor. They compared the number of bad outcomes — from death to broken clavicles — for women depending on where they had their births.

One comparison stands out in the results. From the abstract: “For nulliparous women [those having their first birth], the odds of the primary outcome [that is, any of the negative events] were higher for planned home births” than among those planned for delivery in obstetric units. That is, the home births had higher rates of negative events. The difference is large. Here’s a figure to illustrate:

The error bars show 95% confidence intervals, so you can see the difference between home births and obstetric-unit births is statistically significant at that level. These are the raw comparisons, but the home-versus-obstetric comparison was unchanged when the analysts controlled for age, ethnicity, understanding of English, marital or partner status, body mass index, “deprivation score,” previous pregnancies, and weeks of gestation. Further, by restricting the comparison to uncomplicated pregnancies and excluded all but last-minute c-sections, it seems to be a very strong result.

But what to make of it?

In their conclusion, the authors write:

Our results support a policy of offering healthy nulliparous and multiparous women with low risk pregnancies a choice of birth setting. Adverse perinatal outcomes are uncommon in all settings, while interventions during labour and birth are much less common for births planned in non-obstetric unit settings. For nulliparous women, there is some evidence that planning birth at home is associated with a higher risk of an adverse perinatal outcome.

But in what way do the results “support a policy”? The “higher risks” they found for planned home births are still “uncommon,” by comparison, with those in poor countries, for example. But the home birth risk is 2.7-times greater.

The Skeptical OB, who is a reliable proponent of modern medical births, titled her post, “It’s official: homebirth increases the risk of death.” She added some tables from the supplemental material, showing the type of negative events and conditions that occurred. Her conclusion:

“In other words, any way you choose to look at it, no matter how carefully you slice and dice the data, there is simply no getting around the fact that homebirth increases the risk of perinatal death and brain damage.”

I guess the policy options might include include whether home births should be encouraged, more regulated, covered by public and/or private health insurance, banned, penalized or (further) stigmatized.

Home birth seems safer than letting children ride around unrestrained in the back of pickup trucks, which is legal in North Carolina — as long as they’re engaged in agricultural labor. On the other hand, we have helmet laws for kids on bicycles in many places. And if a child is injured in either situation, hopefully an ambulance would take them to the hospital even if the accident were preventable.

In other words, I don’t think policy questions can be resolved by a comparison of risks, however rigorous.

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