Why Is Infant Mortality Higher in the United States than in Europe?

It’s common knowledge among the Aaron Sorkin segment of the population that the United States has a high infant mortality rate compared to other developed nations. But if you were to ask why, you probably wouldn’t get a good answer; even for researchers the reason has been a bit mysterious. A new paper in the American Economic Journal of Economic Policy provides some answers, but like any good research leads to more questions as well.

Depending on who you ask, as of 2015 the US infant mortality rate (IMR, defined as the number of deaths of infants under one year old per 1000 live births) is around 5.6~5.9. In the EU, the rate is closer to 3.7. In the grand scheme of things we’re actually doing pretty decent; below is a plot of  IMR vs GDP per capita (PPP) for most countries in 2014.



We can see that there is a pretty clear correlation (on the log scale) between the two. Above the trend line is higher IMR than expected for a given per capita GDP, and below is lower. Most rich OECD countries are well below the line; we are slightly above. However, our neighborhood north of the line is mostly rich oil countries like United Arab Emirates, Saudi Arabia, Kuwait, Qatar, etc.; countries that were it nor for oil wealth would be far poorer and shifted to the left. In other words, for an advanced economy we seem to be pretty lonely above the trend line. So what’s going on?

There are three channels that can explain this difference. As is the case with crimes, countries have differing reporting standards for infant mortality, making cross country comparison difficult. For example, an extremely premature birth that doesn’t survive may be counted as a live birth in some countries or as a miscarriage in others, which alters the deaths/live births ratio. A second confounding problem is the incidence of low birth weight (LBW), which is associated with lower survival rates. The US has higher rates of low birth weight than other developed countries, so it could be possible that a higher IMR is a compositional effect, which has its own policy implications. Finally, the timing of deaths is often not available in data. A concentration of higher IMR early on or later in the first year again has very different policy implications. Early on could suggest substandard medical infrastructure, while a random or later distribution indicates some deeper issues.

The authors of ‘Why Is Infant Mortality Higher in the United States Than Europe?’, Alice Chen, Emily Oster, and Heidi Williams, were able to obtain microdata on the US, Austria, and Finland that allowed them to investigate all three of these problems. Particularly, the novel thing was getting access to detailed timing information, which allow distinction between neonatal (within the first month) and post neonatal (months 2-12) deaths.

With regards to reporting differences, some of the higher US IMR is indeed due to differences in reporting. After controlling for this, the average excess US IMR compared with these countries is reduced by about 40%. They also found that higher rates of low birth weight could account for another significant fraction of the US disadvantage, but not all.

The rest of the excess deaths were located in the post neonatal time period, and the graphs in the paper are really quite striking. In LBW children, the three countries perform similarly. In the first month of life with normal birth weight children the US performs comparably to Austria and Finland. But thereafter the probability of death in the US pulls away significantly (all subsequent images are from the paper).




This suggests the high US IMR is not due to any deficiencies in US medical care or facilities; if that were the case, we should expect elevated rates throughout the first year as well as with LBW births. Instead, these deaths are occurring at home.

A  natural follow up is to ask whether this phenomenon is randomly distributed throughout the population or is concentrated in space and/or socioeconomic status. Using the US Census Divisions, they find that the Northeast region performs best, whereas the East South Central (Alabama, Kentucky, Mississippi and Tennessee) performs significantly worse than the rest of the country.




As you may suspect, these areas have very different levels of income, and indeed it seems the main source of the effect is from socioeconomic status.



This research could find no ‘smoking gun’ as to the cause of increased mortality in the first year of life. Again, issues with reporting and coding prevent any clear conclusions. SIDS is hard to correctly diagnose, and the other major causes are the nebulous ‘Accidents’ and ‘Other’.

In the United States the focus has historically been on reducing instances of LBW,  but in light of this paper we can conclude that policies aimed at reducing premature births and/or low birth weight will only go so far. The authors suggest that supporting home nurse visits for new mothers, as is policy in several European countries (including the two analyzed here), could be effective in reducing the infant mortality rate through the mechanism of increased parental knowledge. Clearly this is an understudied topic and more research is needed, particularly into the cause of these deaths.


What’s the Big Idea, Again? (tl;dr)

The United States has a higher infant mortality rate than many other comparably rich countries. This is partly due to differences in reporting and higher incidence of low birth weight, but also due to higher rates of infant mortality in the 2-12th months of life. This phenomenon is concentrated both geographically and economically, particularly among the disadvantaged in areas like the Deep South. Areas like New England, with their higher share of the economically advantaged, see essentially no difference in IMR compared with other rich European countries.


What Do We Do?

I know many people are uncomfortable putting human life in monetary terms, and understandably so. But in certain situations it can be illuminating. The authors use the value of a statistical life, most commonly quoted at around $7 million, to put this in context. Given approximately 4 million births a year, our IMR is ‘costing’ us about $84 billion each year. Which on the flip side, suggests it would be worth spending at least $7,000 per child to reach Austrian levels of infant mortality, and even more if we just focused on disadvantaged births. If that’s the calculus, supporting home nurse visits is a no brainer. And if you think a human life is worth far more than $7 million, then home nurse visits are even more of a no brainer.

It has been argued in the past that in the United States we care deeply about the life of a child until the moment they are born. After that, they’re on their own. And I think this research bears that out to some degree. It’s also another symptom of the increasing levels of inequality here. The advantaged among us, with jobs with generous parental leave, with leisure time to research the dos and don’ts of pregnancy and early life, with the means to afford outside caregivers, are doing fine. Yes, tragedies still happen, but no more than anywhere else in the world. The disadvantaged, the ones who work until they can’t stand anymore, who can’t even take full use of their 12 weeks of unpaid leave because they have to get back to work to pay the bills, are struggling. And in too many instances, failing.

As a society we should be doing more to support disadvantaged mothers and their children. We can argue over what the best course is, whether it is in the form of easy access to family planning services, professional health care in the home, or through more fundamental issues like education or family stability. But I don’t think we can argue that we do enough already. If life begins at conception, then we must also remember it continues after birth.


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