If you’re seeing this in summer 2022, we’ll be posting many submissions in a short period. If you want to stop seeing them so often, apply a filter for the appropriate tag!
Purpose (Note from Author)
The following piece is an investigation into a cause area that, after a shallow review, has potential to be an important funding area for Open Philanthropy. Where relevant, I have explained major sources of uncertainty and kept estimates conservative.
Summary
Preamble: In a lifetime, each individual goes through several critical stages of development. These stages are considered “critical” because these are periods when the nervous system is especially sensitive to environmental stimuli. Most research in the field of development agrees that the most critical period of a person’s life occurs in the first 1000 days from the moment of fertilization. This period includes two developmental stages: prenatal development and infancy and toddlerhood. In the first trimester, the brain grows millions of neurons, setting the foundation for synaptic communication that will govern their nervous system. At birth, a baby’s brain is ¼ the size of an adult’s brain. Through infancy and toddlerhood, the brain reaches 80% of adult weight. Furthermore, it is a time of emotional and cognitive development which will act as a foundation for the remainder of the child’s life. Proper development at this stage is thus critical for both short and long-term individual outcomes.
—
Every year, 140 million children are born. Over the span of 10 years, investing in healthy fetal and early infanthood will affect a population equaling China. In 2015, 20.5 million babies were born with low birth weight (LBW). In 2020, 15 million babies were born pre-term (before 37 weeks of gestation). An estimated 13 million children are born with intraurinal growth retardation (IUGR) due to maternal malnutrition due to pregnancy. In terms of environmental impact on infants, according to the WHO, 92% of the world lives in places where air pollution due to fine particulate matter exceeds the WHO air quality standards. Furthermore, the Covid-19 pandemic has led to significant increases in stress, which was felt strongly by pregnant mothers. In 2017, 10% of newborns in the United States were born to mothers with less than a high school degree. Each abovementioned factor is associated with poor outcomes later in life including earlier mortality, worse health, lower educational attainment and lower life earnings.
The leading cause of DALYs in 2017 were neonatal disorders, including low birth weight and pre-term birth. In 2019, maternal and neonatal disorders caused 200M DALYs. In sub-Saharan Africa alone, neonatal sepsis, a disease caused from a blood infection caused an estimated 5.3-8.3M DALYs in 2014, causing an economic burden of 469 billion US dollars. These numbers underestimate the DALYs from poor neonatal and infant development because they exclude factors like air pollution, maternal nutrition, pregnancy stress, and educational attainment. Given the shallow nature of this investigation, I will not be discussing the effect of poor early development on QALYs and WALYs, because their calculation comes with more uncertainty than DALYs. Nonetheless, these metrics are relevant given that health (to a larger extent) and well-being are already considered important measures for governments, organizations, and policymakers.
Given my shallow investigation, poor short and long-term outcomes can be avoided on a large scale if, in the first 1000 days of an individual’s life, efforts are made to intervene on the environment.
Uncertainties
Here are my major uncertainties about improving short-term and long-term outcomes on a large scale by intervening on development in the early stages of life.
Many studies that observe short and long-term effects of prenatal and early childhood environments are based on correlational data. It is impossible to make causal claims about the benefits of a certain environment using correlational data. This means that both short and long-term outcomes are difficult to causally link (with confidence) to early shocks or environments.
Early childhood shocks are better linked (in terms of larger effect size) to future health outcomes than educational, wage and well-being outcomes. This is probably because there are other important factors which occur in late childhood, adolescence and adulthood which influence these outcomes.
Although not consistent across all studies, the effects of early interventions are most effective for the most disadvantaged children. This means that simply coming from a more advantaged background (e.g., HSES) protects against the effects of maternal stress, air pollution, maternal malnutrition, etc. This calls into question whether early interventions are the most effective way to improve long-term outcomes, as opposed to simply increasing individual or family wealth across the board.
Importance
Poor Early Development is Linked to Worse Long-term Outcomes
Neonatal disorders like preterm birth, LBW and IUGR have been linked to factors like maternal malnutrition, stress during pregnancy, low SES status and pollution exposure (Currie, 2020). In the short-term, these disorders increase mortality risk and result in poorer childhood health. In the long-term, newborns with these disorders bear the toll of poorer adult outcomes in health, education and employment (Currie & Hyson, 1999). Based on a study of 17,000 children born in Great Britain in the late 1950s, LBW has a persistently negative effect on math and English performance. Those born with LBW had a 7% higher probability of reporting fair or poor health. Furthermore, those with LBW had an 8% lower probability of being employed. These effects were relatively constant regardless of SES status.
Environmental deprivation (e.g., lack of play) during the neonatal and infanthood development stages lead to difficulties with social and emotional learning later in life. In adulthood, infants who were deprived of play don’t cope well with stress, are more likely to be unoptimistic and show depressive symptoms. While this is less well studied in humans due to experimental ethics, play activates genes in the prefrontal cortex, an area that is important for executive functions like attention, impulse control, cognitive flexibility and memory. In extreme cases, like institutions which grossly deprive young children from play, emotional connection and cognitive development, neurodevelopmental symptoms (e.g., ADHD symptoms, Autism Spectrum Disorder symptoms, Disinhibited social engagement) which persist into adulthood develop (Golm et al., 2020).
Poor Development is linked to Intergenerational Suffering
Early childhood development has an effect on future generations. In terms of a cause area, this is a positive because it means that the benefits of an intervention could be felt beyond the immediate recipient. Given the literature, the evidence is mixed as to how big of an intergenerational impact exists. In one study, the prenatal exposure of mothers to the violent incidents during the Gwangju Uprising was estimated to reduce the offspring birth weight and length of gestation by 57g and 2.3 days respectively (Lee, 2014). This effect was the strongest if exposure happened during the second trimester, this increased the probability of LBW and preterm birth by 4 and 4.6% respectively. In turn, LBW and preterm birth are related to poor health and socioeconomic outcomes in later life. These results of intergenerational impact point to the possibility that the adverse effects of poor maternal, neonatal, and early infant development, including lost DALYs, QALYs and WELBYs are underestimated.
Reducing Inequality
Children who experience prenatal health shocks are likely to face continued health and other disparities in their adult lives. Those with lower birth weight are more likely to have asthma or ADHD (Currie, 2020). As adults they are more likely to have lower wages, to reside in lower-income areas, or to be on disability-assistance programs. Sibling studies, in which environments are similar and thus pose less of a confounding risk, show that LBW is predictive of increased risk of heart disease, diabetes, obesity and some mental health conditions. LBW is much more common among infants born to poor and minority mothers. In 2016, 13.5% of Black bothers had low-birth weight babies compared with 7% of non-Hispanic white mothers and 7.3% of Hispanic mothers. Furthermore, across the entire U.S, neighborhoods with higher numbers of Black residents had systematically worse air quality than other neighborhoods. In fact, 61% of Black mothers lived within a mile of a site that emitted toxic chemicals like heavy metals or organic carcinogens. This means that systemic housing inequalities which affect infant health, will influence later life outcomes, and continue to affect the next generation. Lastly, maternal stress disproportionally impacts the poor. The main stressors include loneliness. Hormones released during a stress response, primarily cortisol, have been linked to pre-term labor.
Neglectedness
Compared to other causes, which gained support in the upsurge in global health financing in the mid-2010s, maternal, newborn and child health gained the least. In 2008, international funding of maternal, newborn and child health reached 3.17 US$ billion (Ooms et al., 2012). Compared to 1999 numbers, funding for this cause area grew by 202%, while funding for HIV/AIDS, malaria and tuberculosis grew by 1066%, 1544% and 1077% , respectively (Figure 1). One reason for this limited growth may have been the difficulty in delivering interventions targeting maternal, newborn and child health and development. One organization working on this is the Every Woman Every Child initiative– a global movement that urges government, public and private organizations to act on the needs of women and children. Since its launch in 2010, $40 billion has been pledged towards the cause. Private spending by philanthropists like The Bill and Melinda Gates Foundation’s Maternal, Newborn and Child Health Program is also aimed at reducing mortality and increasing the health and well-being of mothers and newborns. This funding has been paying off, reflected in the falling infant mortality rates in the US and across the world. However many successful programs that promise better lives for mothers and children are under attack. These include the Clean Air Act and Medicaid. Furthermore, other indicators that negatively affect a developing fetus, disease and adult outcomes are on the rise like obesity, domestic violence, alcohol consumption and drug overdose.
One of the major roadblocks in funding and results for this cause area is the lack of consensus about which interventions work. I’ve identified several environmental factors, ripe for potential interventions, which have been found to have long-term effects on adult health and material well-being: maternal, newborn, and infant health, pollution, and stress. Based on my research, there is no organization that considers all these factors holistically.
The Financing Global Health Online Tool allows for an in-depth breakdown of all sources of funding for different causes. I’ve added together the global funding for 2020 for the following areas, and where possible included an estimate of the funding per DALY.
HealthFinancing (in 2020) The tool separates newborn and child health from maternal health:
A. Newborn and Child Health: 1. Nutrition: $2 billion 2. Other system support: $1.1 billion 3. Human resources: $330 million 4. Other newborn and child health: $1.3 billion 4. Newborn and child health and vaccines: $3.4 billion B. Maternal Health:
Family Planning: $1.1 billion
Maternal Systems Support: $1.1 billion
Maternal Health: $1.3 billion
Other maternal and reproductive health: $1.1 billion
Reproductive and maternal health (human resources): $270 million
Total Funding: $37 per DALY on maternal, neonatal and nutritional diseases. (BOTEC)
Improving Air Quality Financing
An estimated $1.4 billion was spent in 2019 on projects aimed at improving air quality worldwide. Meanwhile, an estimated 100 million DALYs are caused by air-pollution. Meaning that merely 14$ are spent per DALY caused by air pollution. This is a third of what is spent per DALY caused by malaria. Also, poor air quality is more harmful for newborns and infants because they breathe faster and are undergoing rapid development of critical organs like their brain and lungs. Therefore, they are most susceptible to the negative effects of poor air quality, making the financing per DALY an overestimate in the newborn and infant population.
Reducing Maternal Stress Financing
I’m the most uncertain about the neglectedness of maternal stress on the fetus, newborn and infant. This cause is certainly neglected, since I couldn’t find organizations working on it, but it could be for good reason since this is difficult and possibly impractical to intervene on. I discuss some interventions for reducing maternal stress in the next section.
Beyond the neglect in financing this cause area, there is noticeable inequality in how much is spent on maternal, neonatal and infant development across countries. For example, last year, the US spent $111 billion on national maternal and newborn care. This amounts to 0.5% of the country’s GNI per capita. If we assume that DALYs are spread equally among countries, based on the population of the United States, it should have 4.25% of the total DALYs from Communicable diseases, maternal, neonatal and nutritional diseases. This is certainly an overestimate given that most DALYs from this category occur in LIC countries. If we calculate how much is spent per DALY on maternal and neonatal care in the US, we get $7650/DALY. This is a lower estimate given that less of the total DALYs from this category occur the US. Meanwhile, if LMIC countries spent 0.5% of their country’s GNI per capita, which is an average of $3000, they would be spending 356$/DALY on maternal and neonatal care, less than 1/20th of the amount in the US. And this is an underestimate given that the DALYs I used come from maternal, neonatal and nutritional diseases. This category does not include DALYs that come from early exposure to air pollution and stress which are disproportionally felt by people in LMICs.
In the public sphere, there does seem to be a general understanding for the importance of this developmental period. In 2015, Hillary Clinton gave an address about the importance of the first 1000 days for child development. This speech was primarily about malnutrition, but it captured the idea that the developmental period before 2 years is critical for well-being.
Overall, this cause is neglected compared to others like malaria, tuberculosis and AIDS/HIV. This could be due to a lack of consensus about effective interventions and a non-holistic implementation of them across the critical stages of development.
Tractability
Interventions targeting fetal, newborn and infant health have the advantage of resulting in many short-term and long-term outcomes which can be measured over time. Short-term outcomes are easier to measure because they are typically concerned with objective health measures like mortality, weight and general health. Long-term outcomes are more difficult to measure because they call for objective measures like health and financial well-being, and subjective measures like psychological well-being and self-perceived health.
There are still many unknowns when it comes to the causal mechanisms between implemented interventions and long-term adult outcomes. This is mainly due to the difficulty and cost of tracking participants of interventions throughout their adolescence and adulthood. Second, early childhood outcomes are easier to link to early interventions than adult outcomes since there are less potential intermediate variables which could be either partially or fully explaining the outcomes. This is why many interventions, that could potentially have a big impact, haven’t been discovered or implemented yet at scale. One way that we could stimulate progress in this area is to fund projects that are testing different interventions (some of which have been described below) over the long-term because only a small fraction of studies actually collect long-term outcomes.
Name of Intervention
Potential
Fund Research, Fund Directly, Advocate For?
Providing Basic Provisions and Services
High
Fund Directly, Advocate For
Psychosocial Stimulation
Medium
Fund Research, Fund Directly
Nutrition
High
Advocate
Reducing Pregnancy Stress
Medium
Fund Research, Advocate For
Reducing Exposure to Pollution
High
Fund Directly, Advocate For
Increasing Educational Access
Medium
Fund Directly, Advocate For
Cash-Transfers
Medium
Fund Directly
Early Childhood Stimulation
Medium
Fund Directly, Advocate For
Research into Interim and Long-term Outcomes
Medium-High
Fund Research
Possible Interventions
Basic Provisions and Services
Pregnant mothers in the tens of millions do not receive adequate pregnancy-related and
newborn healthcare. This includes not delivering in a healthcare facility, making less than four antenatal care visits and not receiving postnatal care like home visits and breastfeeding training. Based on a meta-analysis of 19 studies, delivering in a healthcare facility reduced the risk of neonatal mortality by 29%. This is a significant increase in the likelihood of infant survival. Paired with the reduction of risk of maternal mortality and the fact that delivering in a sterile healthcare facility avoids potentially damaging exposure to infection whose effects may accumulate over a lifetime causing earlier mortality or greater susceptibility to sickness, expanding access to healthcare facilities and encouraging mothers to in fact deliver in them would greatly reduce the mortality rate and DALYs. Most of my uncertainty here stems from how much the effect propagates throughout a lifespan.
Antenatal care like testing and treatment for HIV and other STIs can greatly reduce the risk of preterm delivery and low birthweight. While these screening tests are standard practice in HICs, mothers in LMICs are routinely underserved. A meta-analysis of 18 studies found that the risk of neonatal death was reduced by 34% in mothers who had antenatal care visits.
As for postnatal care, which includes both routine and emergency health needs of both mother and child, only 36% of mothers in LMICs receive it. I’ve also included (in the definition of postnatal care), physical examinations of infants in the first year of life as well as information provided about normal development, sleep, safety, disease and nutrition. This care was found, in a cohort study in Norway, to lead to increase in education levels (0.15 more time spent in school), lifetime earnings (by 2%), and reduced health risks at the age of 40.
Psychosocial Stimulation
Beyond basic provisions, the first two years of life require social and emotional stimulation that will equip a child with the necessary foundations to develop healthy attachments and coping strategies. A study run in Jamaica tested the impact of psychosocial stimulation on long-term outcomes of growth-stunted children. Causes of growth-stunting include malnutrition and repeated infection. The long term consequences of growth-stunting include poor cognition, educational performance and low adult wages. In 2008, child stunting accounted for ~22 million DALYs per year. The stimulation included two years of supervised weekly one-hour play sessions at home which were designed to develop a child’s cognitive, language and psychosocial skills. The cohort given the stimulation, when surveyed 20 years later, were found to have 25% higher incomes than those of the control group, and similar incomes to the non-growth stunted comparison group. In effect, this randomized intervention showed causal mechanisms which compensated for an early disadvantage and reduced later life inequality.
Nutrition
Basic maternal nutrition plays an important role in fetal, neonatal and infant health. This in turn affects long-term health, well-being and educational outcomes. Both malnutrition and obesity can be detrimental to long-term outcomes. According to the WHO, maternal malnutrition, specifically, mothers in the lowest quartile of attained weight by the 5th month of pregnancy increases the odds ratio of LBW, pre-term birth and IUGR to 2.4, 0.9 and 3.0 respectively. In terms of long-term outcomes, maternal exposure to famine decreased literacy rates by 1.1%. Illiteracy has a big economic, social and even health impact. The World Literacy Foundation found that illiteracy cost the global economy $960 billion US dollars due to welfare, unemployment, reduced government tax revenue and productivity.
On the other end of the nutrition spectrum, one study found that high maternal pre-pregnancy weight (in the top tertile) increased the prevalence of asthma in 15-16 years olds by a factor of 1.3. Also pregnancy obesity increased ADHD diagnoses by 67%. In turn, a study found that young adults diagnosed with ADHD between ages 23 and 32 are 11 times more likely to be unemployed and not in school. They also earned close to $2 per hour less in wages than the comparison group .
Many organizations are already working on reducing malnutrition. So this space is likely
saturated for new philanthropists. However, the fight with obesity, whose incidence has tripled since 1975 is far from over, but can have a significant impact on newborn health and long-term adult outcomes. Work in this area can range from advocacy surrounding better nutrition in schools and lobbying food manufacturers to reduce the amount of cholesterol, sugars and salt in foods. Furthermore, while rates of malnutrition are dropping, obesity rates are increasing. From 1990 to 2017, global deaths and DALYs from high BMI doubled. In 2019, this number was 160M DALYs. I am fairly certain that this is an underestimate considering the lasting effects of pregnancy obesity on children born to mothers with a high BMI index.
Reducing Pregnancy Stress
In 2021, according to the Gallup World Poll, the number of people reporting feelings of worry, sadness and stress exceeded numbers in the past 16 years. This likely had close connection to the Covid-19 pandemic and the stress individuals and communities felt in response to job loss, sickness and death. A study of a cohort of mothers found that in-utero exposure of to stress during the second trimester exerted the strongest adverse effect on offspring birth outcomes. This means that the effects of pre-natal shocks propagate through generations and incite more suffering and economic cost than is likely being assumed by policy-makers. Furthermore, a number of studies find that prenatal stress is associated with generational lifespan attachment difficulties, stress-hyperresponsiveness asthma, allergies, a difficult temperament and affective disorders.
Furthermore, pregnancy stress is a source of inequality since it, presumably, affects LSES households disproportionately. As a result, inequality propagates since the effects would be more acutely felt in LSES households.
Three categories of interventions have shown promise in reducing pregnancy stress. First is relaxation training, which showed a decrease in incidence of LBW. Second is conducting a psychosocial analysis and identifying the source of stress in pregnant mothers and directing them to the appropriate services. The last category of intervention is social support in the form of visits from midwives and phone calls. This last category has been the least successful in providing a protective factor against neonatal disorders.
A way to directly decrease maternal pregnancy stress is to lobby for longer period of paid pregnancy leave. In Ontario, Canada, pregnant mothers are entitled to 17 weeks of paid pregnancy leave. Almost all of this time is restricted to the third trimester. This is the current policy despite the knowledge that a lot of critical development happens in the second trimester which starts 24 weeks before the due date.
Reducing Pollution
Pollution is a nefarious way that inequality propagates through generations. Exposure to levels of air pollution exceeding WHO standards increases the risk of LBW and preterm birth by 2-36% and 11.5% respectively for whole-pregnancy exposure to air pollution. Furthermore, several studies show that higher pollution has a bearing on test scores. In-utero CO exposure has shows significant negative effects on fourth grade math scores.
Some promising avenues of interventions include a 2011 study which looked at the reduction in LBW and preterm birth incidents by 10.8 and 11.8 percent after the introduction of an E-ZPass which reduced vehicle emissions and traffic congestion. Reducing consumption of drinking water pollution also shows promise given that drinking contaminated water increased the probability of low birth rate by 6.5%. Relatively little studies have looked at improving HVAC systems in homes and long-term outcomes. This could prove particularly critical early in infanthood, since at this age, newborns’ immune systems are more sensitive. Hypothetically this could prove useful if homes and the infants immediate environment contains higher than recommended levels of air pollution.
Increasing Educational Access
Increasing educational access to women is a way to indirectly increase the long-term health and economic outcomes of their children. This is, of course, in addition to the benefits that will be reaped by the mothers themselves. For example, the odds ratio of IURG is 1.5 for mothers with a high school education or less. These effects are indirect because lack of education explains the behaviors of women during pregnancy, from health-related behaviors like smoking and alcohol use, to higher likelihood of work-related stress, which are known to worsen both short-term and long-term outcomes for children.
According to a UN report, half a billion girls over 15 are illiterate and only 39% rural girls attend secondary school. The World Bank found that limiting opportunities for girls to completing 12 years of schooling cost countries a minimum of $15 trillion in lost lifetime productivity and earnings. This is a conservative cost given the intergenerational health and economical costs. Interventions in this domain can focus on increasing educational access to women and sponsoring programs which provide direct education related to healthy pregnancy behaviors could reduce the instances of unhealthy behaviors during pregnancy. Existing efforts in this area are led by UNESCO who have written a framework outlining the steps to the goal of attaining inclusive and equitable education for all by 2030. However, for this goal UNESCO has identified a $200 billion financing shortfall in 2022, likely exacerbated by pandemic costs.
Cash-Transfers
Cash transfers provide an immediate influx of purchasing power for recipients, increasing their health and economic situations. In 2007, a universal child benefit (a one time transfer of $2560 USD) was introduced in Spain. The cash-transfer was associated with a decline in LBW, driven by faster intrauterine growth. The authors even supposed that these early cash-transfers may be more effective than later cash-transfers, given the persisting positive health effects for infants which lead to better long-term outcomes. This effect was stronger for children from disadvantaged backgrounds (e.g., single-parent, low SES household). The literature on cash-transfers at or around the pregnancy period shows different effects depending on the timing of the transfer during pregnancy. For example, some studies find the largest effects when the cash-transfer occurs in the third trimester of pregnancy. Others find the benefit has an expiry date, and suggest that cash-transfers should be made shortly before pregnancy.
Early Childhood Stimulation
Cognitive development is critical in the early stages of an infant’s life. At this stage the child’s brain develops incredibly fast, gaining 80% of the adult brain weight. Furthermore, this period is characterized by high brain plasticity and neurogenesis, making this an important period for the right neural connections to form. Jean Piaget called the developmental period between 0 and 2 years of age the sensorimotor period, where children use their senses and actions to learn and grow. New estimates show that 250 million children younger than 5 years in LMICs are at risk of not reaching their developmental potential.
Early Childhood Stimulation (ECS) shows promise in helping children development. ECS is the interaction between children and caregivers, giving children the opportunity to interact with their environments and stimulating development. Interactions can be as simple as playing, reading, singing, asking questions, etc. JPAL conducted a review of 17 randomized evaluations from 11 LMIC countries which show that programs that encourage caregivers to implement ECS in their homes lead to more time being dedicated to it and increased cognitive development. Long-term outcomes are mixed, with some studies showing long-term impact of ECS lasts beyond 20 years, others with effects disappearing after 2. However, only one long-term study has tracked 20 years, and thus more evidence is needed. Studies show that the most disadvantaged are usually those that stand the most to gain.
Already, studies on interventions for children (0-3) are showing promising results on adult wages, educational attainment, general intelligence, health markers, reductions in violence, depressive symptoms, and growth in future generations.
Research into Interim and Long-term Outcomes
Much of the uncertainty about long-term impacts of neonatal and infant developmental care stems from the lack of research into the medium and long-term outcomes of certain interventions or natural experiments. At the outset this research is more expensive, more time consuming and suffers from attrition bias due to study participants moving or dropping out of the study.
Also, long-term research suffers from higher uncertainty and is thus pursued less in the research community. There are many intermediate factors that can affect a person between an intervention and a long-term outcome. This increases the noise in the measurement and leads to less definitive evidence about the effects of an intervention on long-term outcomes. Research into intermediate and long-term outcomes of interventions is a potential area for funding since it will generate more evidence for or against a given solution. In turn, this will lead to a consensus about an array of effective interventions which deliver results. This list is currently lacking and thus holding back this cause area from being funded.
Conclusion
Healthy fetal, newborn and infant development is critical for both short and long-term individual outcomes. Poor maternal nutrition, maternal stress, air quality, lack of education and an early environment not suited for healthy cognitive and emotional development lead to persistent negative outcomes in later life. Currently, there is a lack of a holistic approach to addressing the needs and development of young children. This is both due to a lack in consensus of effective interventions, and the difficulty in rolling them out at scale. However, given that we are likely underestimating the DALYs and QALYs caused by poor early development, and the potential intergenerational benefits of interventions, this is a cause area that should be considered for funding by Open Philanthropy.
Currie, J., & Hyson, R. (1999). Is the Impact of Health Shocks Cushioned by Socioeconomic Status? The Case of Low Birthweight (Working Paper No. 6999). National Bureau of Economic Research. https://doi.org/10.3386/w6999 Golm, D., Maughan, B., Barker, E. D., Hill, J., Kennedy, M., Knights, N., Kreppner, J., Kumsta, R.,
Schlotz, W., Rutter, M., & Sonuga-Barke, E. J. S. (2020). Why does early childhood deprivation increase the risk for depression and anxiety in adulthood? A developmental cascade model. Journal of Child Psychology and Psychiatry, 61(9), 1043–1053. https://doi.org/10.1111/jcpp.13205
Lee, C. (2014). Intergenerational health consequences of in utero exposure to maternal stress: Evidence from the 1980 Kwangju uprising. Social Science & Medicine (1982), 119, 284–291. https://doi.org/10.1016/j.socscimed.2014.07.001
Ooms, G., Hammonds, R., Richard, F., & De Brouwere, V. (2012). The global health financing revolution: Why maternal health is missing the boat. Facts, Views & Vision in ObGyn, 4(1), 11–17.
[Cause Exploration Prizes] Investment in Fetal, Neonatal and Infant Development
This essay was submitted to Open Philanthropy’s Cause Exploration Prizes contest.
If you’re seeing this in summer 2022, we’ll be posting many submissions in a short period. If you want to stop seeing them so often, apply a filter for the appropriate tag!
Purpose (Note from Author)
The following piece is an investigation into a cause area that, after a shallow review, has potential to be an important funding area for Open Philanthropy. Where relevant, I have explained major sources of uncertainty and kept estimates conservative.
Summary
Preamble: In a lifetime, each individual goes through several critical stages of development. These stages are considered “critical” because these are periods when the nervous system is especially sensitive to environmental stimuli. Most research in the field of development agrees that the most critical period of a person’s life occurs in the first 1000 days from the moment of fertilization. This period includes two developmental stages: prenatal development and infancy and toddlerhood. In the first trimester, the brain grows millions of neurons, setting the foundation for synaptic communication that will govern their nervous system. At birth, a baby’s brain is ¼ the size of an adult’s brain. Through infancy and toddlerhood, the brain reaches 80% of adult weight. Furthermore, it is a time of emotional and cognitive development which will act as a foundation for the remainder of the child’s life. Proper development at this stage is thus critical for both short and long-term individual outcomes.
—
Every year, 140 million children are born. Over the span of 10 years, investing in healthy fetal and early infanthood will affect a population equaling China. In 2015, 20.5 million babies were born with low birth weight (LBW). In 2020, 15 million babies were born pre-term (before 37 weeks of gestation). An estimated 13 million children are born with intraurinal growth retardation (IUGR) due to maternal malnutrition due to pregnancy. In terms of environmental impact on infants, according to the WHO, 92% of the world lives in places where air pollution due to fine particulate matter exceeds the WHO air quality standards. Furthermore, the Covid-19 pandemic has led to significant increases in stress, which was felt strongly by pregnant mothers. In 2017, 10% of newborns in the United States were born to mothers with less than a high school degree. Each abovementioned factor is associated with poor outcomes later in life including earlier mortality, worse health, lower educational attainment and lower life earnings.
The leading cause of DALYs in 2017 were neonatal disorders, including low birth weight and pre-term birth. In 2019, maternal and neonatal disorders caused 200M DALYs. In sub-Saharan Africa alone, neonatal sepsis, a disease caused from a blood infection caused an estimated 5.3-8.3M DALYs in 2014, causing an economic burden of 469 billion US dollars. These numbers underestimate the DALYs from poor neonatal and infant development because they exclude factors like air pollution, maternal nutrition, pregnancy stress, and educational attainment. Given the shallow nature of this investigation, I will not be discussing the effect of poor early development on QALYs and WALYs, because their calculation comes with more uncertainty than DALYs. Nonetheless, these metrics are relevant given that health (to a larger extent) and well-being are already considered important measures for governments, organizations, and policymakers.
Given my shallow investigation, poor short and long-term outcomes can be avoided on a large scale if, in the first 1000 days of an individual’s life, efforts are made to intervene on the environment.
Uncertainties
Here are my major uncertainties about improving short-term and long-term outcomes on a large scale by intervening on development in the early stages of life.
Many studies that observe short and long-term effects of prenatal and early childhood environments are based on correlational data. It is impossible to make causal claims about the benefits of a certain environment using correlational data. This means that both short and long-term outcomes are difficult to causally link (with confidence) to early shocks or environments.
Early childhood shocks are better linked (in terms of larger effect size) to future health outcomes than educational, wage and well-being outcomes. This is probably because there are other important factors which occur in late childhood, adolescence and adulthood which influence these outcomes.
Although not consistent across all studies, the effects of early interventions are most effective for the most disadvantaged children. This means that simply coming from a more advantaged background (e.g., HSES) protects against the effects of maternal stress, air pollution, maternal malnutrition, etc. This calls into question whether early interventions are the most effective way to improve long-term outcomes, as opposed to simply increasing individual or family wealth across the board.
Importance
Poor Early Development is Linked to Worse Long-term Outcomes
Neonatal disorders like preterm birth, LBW and IUGR have been linked to factors like maternal malnutrition, stress during pregnancy, low SES status and pollution exposure (Currie, 2020). In the short-term, these disorders increase mortality risk and result in poorer childhood health. In the long-term, newborns with these disorders bear the toll of poorer adult outcomes in health, education and employment (Currie & Hyson, 1999). Based on a study of 17,000 children born in Great Britain in the late 1950s, LBW has a persistently negative effect on math and English performance. Those born with LBW had a 7% higher probability of reporting fair or poor health. Furthermore, those with LBW had an 8% lower probability of being employed. These effects were relatively constant regardless of SES status.
Environmental deprivation (e.g., lack of play) during the neonatal and infanthood development stages lead to difficulties with social and emotional learning later in life. In adulthood, infants who were deprived of play don’t cope well with stress, are more likely to be unoptimistic and show depressive symptoms. While this is less well studied in humans due to experimental ethics, play activates genes in the prefrontal cortex, an area that is important for executive functions like attention, impulse control, cognitive flexibility and memory. In extreme cases, like institutions which grossly deprive young children from play, emotional connection and cognitive development, neurodevelopmental symptoms (e.g., ADHD symptoms, Autism Spectrum Disorder symptoms, Disinhibited social engagement) which persist into adulthood develop (Golm et al., 2020).
Poor Development is linked to Intergenerational Suffering
Early childhood development has an effect on future generations. In terms of a cause area, this is a positive because it means that the benefits of an intervention could be felt beyond the immediate recipient. Given the literature, the evidence is mixed as to how big of an intergenerational impact exists. In one study, the prenatal exposure of mothers to the violent incidents during the Gwangju Uprising was estimated to reduce the offspring birth weight and length of gestation by 57g and 2.3 days respectively (Lee, 2014). This effect was the strongest if exposure happened during the second trimester, this increased the probability of LBW and preterm birth by 4 and 4.6% respectively. In turn, LBW and preterm birth are related to poor health and socioeconomic outcomes in later life. These results of intergenerational impact point to the possibility that the adverse effects of poor maternal, neonatal, and early infant development, including lost DALYs, QALYs and WELBYs are underestimated.
Reducing Inequality
Children who experience prenatal health shocks are likely to face continued health and other disparities in their adult lives. Those with lower birth weight are more likely to have asthma or ADHD (Currie, 2020). As adults they are more likely to have lower wages, to reside in lower-income areas, or to be on disability-assistance programs. Sibling studies, in which environments are similar and thus pose less of a confounding risk, show that LBW is predictive of increased risk of heart disease, diabetes, obesity and some mental health conditions. LBW is much more common among infants born to poor and minority mothers. In 2016, 13.5% of Black bothers had low-birth weight babies compared with 7% of non-Hispanic white mothers and 7.3% of Hispanic mothers. Furthermore, across the entire U.S, neighborhoods with higher numbers of Black residents had systematically worse air quality than other neighborhoods. In fact, 61% of Black mothers lived within a mile of a site that emitted toxic chemicals like heavy metals or organic carcinogens. This means that systemic housing inequalities which affect infant health, will influence later life outcomes, and continue to affect the next generation. Lastly, maternal stress disproportionally impacts the poor. The main stressors include loneliness. Hormones released during a stress response, primarily cortisol, have been linked to pre-term labor.
Neglectedness
Compared to other causes, which gained support in the upsurge in global health financing in the mid-2010s, maternal, newborn and child health gained the least. In 2008, international funding of maternal, newborn and child health reached 3.17 US$ billion (Ooms et al., 2012). Compared to 1999 numbers, funding for this cause area grew by 202%, while funding for HIV/AIDS, malaria and tuberculosis grew by 1066%, 1544% and 1077% , respectively (Figure 1). One reason for this limited growth may have been the difficulty in delivering interventions targeting maternal, newborn and child health and development. One organization working on this is the Every Woman Every Child initiative– a global movement that urges government, public and private organizations to act on the needs of women and children. Since its launch in 2010, $40 billion has been pledged towards the cause. Private spending by philanthropists like The Bill and Melinda Gates Foundation’s Maternal, Newborn and Child Health Program is also aimed at reducing mortality and increasing the health and well-being of mothers and newborns. This funding has been paying off, reflected in the falling infant mortality rates in the US and across the world. However many successful programs that promise better lives for mothers and children are under attack. These include the Clean Air Act and Medicaid. Furthermore, other indicators that negatively affect a developing fetus, disease and adult outcomes are on the rise like obesity, domestic violence, alcohol consumption and drug overdose.
One of the major roadblocks in funding and results for this cause area is the lack of consensus about which interventions work. I’ve identified several environmental factors, ripe for potential interventions, which have been found to have long-term effects on adult health and material well-being: maternal, newborn, and infant health, pollution, and stress. Based on my research, there is no organization that considers all these factors holistically.
The Financing Global Health Online Tool allows for an in-depth breakdown of all sources of funding for different causes. I’ve added together the global funding for 2020 for the following areas, and where possible included an estimate of the funding per DALY.
Health Financing (in 2020)
The tool separates newborn and child health from maternal health:
A. Newborn and Child Health:
1. Nutrition: $2 billion
2. Other system support: $1.1 billion
3. Human resources: $330 million
4. Other newborn and child health: $1.3 billion
4. Newborn and child health and vaccines: $3.4 billion
B. Maternal Health:
Family Planning: $1.1 billion
Maternal Systems Support: $1.1 billion
Maternal Health: $1.3 billion
Other maternal and reproductive health: $1.1 billion
Reproductive and maternal health (human resources): $270 million
Total Funding: $37 per DALY on maternal, neonatal and nutritional diseases. (BOTEC)
Improving Air Quality Financing
An estimated $1.4 billion was spent in 2019 on projects aimed at improving air quality worldwide. Meanwhile, an estimated 100 million DALYs are caused by air-pollution. Meaning that merely 14$ are spent per DALY caused by air pollution. This is a third of what is spent per DALY caused by malaria. Also, poor air quality is more harmful for newborns and infants because they breathe faster and are undergoing rapid development of critical organs like their brain and lungs. Therefore, they are most susceptible to the negative effects of poor air quality, making the financing per DALY an overestimate in the newborn and infant population.
Reducing Maternal Stress Financing
I’m the most uncertain about the neglectedness of maternal stress on the fetus, newborn and infant. This cause is certainly neglected, since I couldn’t find organizations working on it, but it could be for good reason since this is difficult and possibly impractical to intervene on. I discuss some interventions for reducing maternal stress in the next section.
Beyond the neglect in financing this cause area, there is noticeable inequality in how much is spent on maternal, neonatal and infant development across countries. For example, last year, the US spent $111 billion on national maternal and newborn care. This amounts to 0.5% of the country’s GNI per capita. If we assume that DALYs are spread equally among countries, based on the population of the United States, it should have 4.25% of the total DALYs from Communicable diseases, maternal, neonatal and nutritional diseases. This is certainly an overestimate given that most DALYs from this category occur in LIC countries. If we calculate how much is spent per DALY on maternal and neonatal care in the US, we get $7650/DALY. This is a lower estimate given that less of the total DALYs from this category occur the US. Meanwhile, if LMIC countries spent 0.5% of their country’s GNI per capita, which is an average of $3000, they would be spending 356$/DALY on maternal and neonatal care, less than 1/20th of the amount in the US. And this is an underestimate given that the DALYs I used come from maternal, neonatal and nutritional diseases. This category does not include DALYs that come from early exposure to air pollution and stress which are disproportionally felt by people in LMICs.
In the public sphere, there does seem to be a general understanding for the importance of this developmental period. In 2015, Hillary Clinton gave an address about the importance of the first 1000 days for child development. This speech was primarily about malnutrition, but it captured the idea that the developmental period before 2 years is critical for well-being.
Overall, this cause is neglected compared to others like malaria, tuberculosis and AIDS/HIV. This could be due to a lack of consensus about effective interventions and a non-holistic implementation of them across the critical stages of development.
Tractability
Interventions targeting fetal, newborn and infant health have the advantage of resulting in many short-term and long-term outcomes which can be measured over time. Short-term outcomes are easier to measure because they are typically concerned with objective health measures like mortality, weight and general health. Long-term outcomes are more difficult to measure because they call for objective measures like health and financial well-being, and subjective measures like psychological well-being and self-perceived health.
There are still many unknowns when it comes to the causal mechanisms between implemented interventions and long-term adult outcomes. This is mainly due to the difficulty and cost of tracking participants of interventions throughout their adolescence and adulthood. Second, early childhood outcomes are easier to link to early interventions than adult outcomes since there are less potential intermediate variables which could be either partially or fully explaining the outcomes. This is why many interventions, that could potentially have a big impact, haven’t been discovered or implemented yet at scale. One way that we could stimulate progress in this area is to fund projects that are testing different interventions (some of which have been described below) over the long-term because only a small fraction of studies actually collect long-term outcomes.
Possible Interventions
Basic Provisions and Services
Pregnant mothers in the tens of millions do not receive adequate pregnancy-related and
newborn healthcare. This includes not delivering in a healthcare facility, making less than four antenatal care visits and not receiving postnatal care like home visits and breastfeeding training. Based on a meta-analysis of 19 studies, delivering in a healthcare facility reduced the risk of neonatal mortality by 29%. This is a significant increase in the likelihood of infant survival. Paired with the reduction of risk of maternal mortality and the fact that delivering in a sterile healthcare facility avoids potentially damaging exposure to infection whose effects may accumulate over a lifetime causing earlier mortality or greater susceptibility to sickness, expanding access to healthcare facilities and encouraging mothers to in fact deliver in them would greatly reduce the mortality rate and DALYs. Most of my uncertainty here stems from how much the effect propagates throughout a lifespan.
Antenatal care like testing and treatment for HIV and other STIs can greatly reduce the risk of preterm delivery and low birthweight. While these screening tests are standard practice in HICs, mothers in LMICs are routinely underserved. A meta-analysis of 18 studies found that the risk of neonatal death was reduced by 34% in mothers who had antenatal care visits.
As for postnatal care, which includes both routine and emergency health needs of both mother and child, only 36% of mothers in LMICs receive it. I’ve also included (in the definition of postnatal care), physical examinations of infants in the first year of life as well as information provided about normal development, sleep, safety, disease and nutrition. This care was found, in a cohort study in Norway, to lead to increase in education levels (0.15 more time spent in school), lifetime earnings (by 2%), and reduced health risks at the age of 40.
Psychosocial Stimulation
Beyond basic provisions, the first two years of life require social and emotional stimulation that will equip a child with the necessary foundations to develop healthy attachments and coping strategies. A study run in Jamaica tested the impact of psychosocial stimulation on long-term outcomes of growth-stunted children. Causes of growth-stunting include malnutrition and repeated infection. The long term consequences of growth-stunting include poor cognition, educational performance and low adult wages. In 2008, child stunting accounted for ~22 million DALYs per year. The stimulation included two years of supervised weekly one-hour play sessions at home which were designed to develop a child’s cognitive, language and psychosocial skills. The cohort given the stimulation, when surveyed 20 years later, were found to have 25% higher incomes than those of the control group, and similar incomes to the non-growth stunted comparison group. In effect, this randomized intervention showed causal mechanisms which compensated for an early disadvantage and reduced later life inequality.
Nutrition
Basic maternal nutrition plays an important role in fetal, neonatal and infant health. This in turn affects long-term health, well-being and educational outcomes. Both malnutrition and obesity can be detrimental to long-term outcomes. According to the WHO, maternal malnutrition, specifically, mothers in the lowest quartile of attained weight by the 5th month of pregnancy increases the odds ratio of LBW, pre-term birth and IUGR to 2.4, 0.9 and 3.0 respectively. In terms of long-term outcomes, maternal exposure to famine decreased literacy rates by 1.1%. Illiteracy has a big economic, social and even health impact. The World Literacy Foundation found that illiteracy cost the global economy $960 billion US dollars due to welfare, unemployment, reduced government tax revenue and productivity.
On the other end of the nutrition spectrum, one study found that high maternal pre-pregnancy weight (in the top tertile) increased the prevalence of asthma in 15-16 years olds by a factor of 1.3. Also pregnancy obesity increased ADHD diagnoses by 67%. In turn, a study found that young adults diagnosed with ADHD between ages 23 and 32 are 11 times more likely to be unemployed and not in school. They also earned close to $2 per hour less in wages than the comparison group .
Many organizations are already working on reducing malnutrition. So this space is likely
saturated for new philanthropists. However, the fight with obesity, whose incidence has tripled since 1975 is far from over, but can have a significant impact on newborn health and long-term adult outcomes. Work in this area can range from advocacy surrounding better nutrition in schools and lobbying food manufacturers to reduce the amount of cholesterol, sugars and salt in foods. Furthermore, while rates of malnutrition are dropping, obesity rates are increasing. From 1990 to 2017, global deaths and DALYs from high BMI doubled. In 2019, this number was 160M DALYs. I am fairly certain that this is an underestimate considering the lasting effects of pregnancy obesity on children born to mothers with a high BMI index.
Reducing Pregnancy Stress
In 2021, according to the Gallup World Poll, the number of people reporting feelings of worry, sadness and stress exceeded numbers in the past 16 years. This likely had close connection to the Covid-19 pandemic and the stress individuals and communities felt in response to job loss, sickness and death. A study of a cohort of mothers found that in-utero exposure of to stress during the second trimester exerted the strongest adverse effect on offspring birth outcomes. This means that the effects of pre-natal shocks propagate through generations and incite more suffering and economic cost than is likely being assumed by policy-makers. Furthermore, a number of studies find that prenatal stress is associated with generational lifespan attachment difficulties, stress-hyperresponsiveness asthma, allergies, a difficult temperament and affective disorders.
Furthermore, pregnancy stress is a source of inequality since it, presumably, affects LSES households disproportionately. As a result, inequality propagates since the effects would be more acutely felt in LSES households.
Three categories of interventions have shown promise in reducing pregnancy stress. First is relaxation training, which showed a decrease in incidence of LBW. Second is conducting a psychosocial analysis and identifying the source of stress in pregnant mothers and directing them to the appropriate services. The last category of intervention is social support in the form of visits from midwives and phone calls. This last category has been the least successful in providing a protective factor against neonatal disorders.
A way to directly decrease maternal pregnancy stress is to lobby for longer period of paid pregnancy leave. In Ontario, Canada, pregnant mothers are entitled to 17 weeks of paid pregnancy leave. Almost all of this time is restricted to the third trimester. This is the current policy despite the knowledge that a lot of critical development happens in the second trimester which starts 24 weeks before the due date.
Reducing Pollution
Pollution is a nefarious way that inequality propagates through generations. Exposure to levels of air pollution exceeding WHO standards increases the risk of LBW and preterm birth by 2-36% and 11.5% respectively for whole-pregnancy exposure to air pollution. Furthermore, several studies show that higher pollution has a bearing on test scores. In-utero CO exposure has shows significant negative effects on fourth grade math scores.
Some promising avenues of interventions include a 2011 study which looked at the reduction in LBW and preterm birth incidents by 10.8 and 11.8 percent after the introduction of an E-ZPass which reduced vehicle emissions and traffic congestion. Reducing consumption of drinking water pollution also shows promise given that drinking contaminated water increased the probability of low birth rate by 6.5%. Relatively little studies have looked at improving HVAC systems in homes and long-term outcomes. This could prove particularly critical early in infanthood, since at this age, newborns’ immune systems are more sensitive. Hypothetically this could prove useful if homes and the infants immediate environment contains higher than recommended levels of air pollution.
Increasing Educational Access
Increasing educational access to women is a way to indirectly increase the long-term health and economic outcomes of their children. This is, of course, in addition to the benefits that will be reaped by the mothers themselves. For example, the odds ratio of IURG is 1.5 for mothers with a high school education or less. These effects are indirect because lack of education explains the behaviors of women during pregnancy, from health-related behaviors like smoking and alcohol use, to higher likelihood of work-related stress, which are known to worsen both short-term and long-term outcomes for children.
According to a UN report, half a billion girls over 15 are illiterate and only 39% rural girls attend secondary school. The World Bank found that limiting opportunities for girls to completing 12 years of schooling cost countries a minimum of $15 trillion in lost lifetime productivity and earnings. This is a conservative cost given the intergenerational health and economical costs. Interventions in this domain can focus on increasing educational access to women and sponsoring programs which provide direct education related to healthy pregnancy behaviors could reduce the instances of unhealthy behaviors during pregnancy. Existing efforts in this area are led by UNESCO who have written a framework outlining the steps to the goal of attaining inclusive and equitable education for all by 2030. However, for this goal UNESCO has identified a $200 billion financing shortfall in 2022, likely exacerbated by pandemic costs.
Cash-Transfers
Cash transfers provide an immediate influx of purchasing power for recipients, increasing their health and economic situations. In 2007, a universal child benefit (a one time transfer of $2560 USD) was introduced in Spain. The cash-transfer was associated with a decline in LBW, driven by faster intrauterine growth. The authors even supposed that these early cash-transfers may be more effective than later cash-transfers, given the persisting positive health effects for infants which lead to better long-term outcomes. This effect was stronger for children from disadvantaged backgrounds (e.g., single-parent, low SES household). The literature on cash-transfers at or around the pregnancy period shows different effects depending on the timing of the transfer during pregnancy. For example, some studies find the largest effects when the cash-transfer occurs in the third trimester of pregnancy. Others find the benefit has an expiry date, and suggest that cash-transfers should be made shortly before pregnancy.
Early Childhood Stimulation
Cognitive development is critical in the early stages of an infant’s life. At this stage the child’s brain develops incredibly fast, gaining 80% of the adult brain weight. Furthermore, this period is characterized by high brain plasticity and neurogenesis, making this an important period for the right neural connections to form. Jean Piaget called the developmental period between 0 and 2 years of age the sensorimotor period, where children use their senses and actions to learn and grow. New estimates show that 250 million children younger than 5 years in LMICs are at risk of not reaching their developmental potential.
Early Childhood Stimulation (ECS) shows promise in helping children development. ECS is the interaction between children and caregivers, giving children the opportunity to interact with their environments and stimulating development. Interactions can be as simple as playing, reading, singing, asking questions, etc. JPAL conducted a review of 17 randomized evaluations from 11 LMIC countries which show that programs that encourage caregivers to implement ECS in their homes lead to more time being dedicated to it and increased cognitive development. Long-term outcomes are mixed, with some studies showing long-term impact of ECS lasts beyond 20 years, others with effects disappearing after 2. However, only one long-term study has tracked 20 years, and thus more evidence is needed. Studies show that the most disadvantaged are usually those that stand the most to gain.
Already, studies on interventions for children (0-3) are showing promising results on adult wages, educational attainment, general intelligence, health markers, reductions in violence, depressive symptoms, and growth in future generations.
Research into Interim and Long-term Outcomes
Much of the uncertainty about long-term impacts of neonatal and infant developmental care stems from the lack of research into the medium and long-term outcomes of certain interventions or natural experiments. At the outset this research is more expensive, more time consuming and suffers from attrition bias due to study participants moving or dropping out of the study.
Also, long-term research suffers from higher uncertainty and is thus pursued less in the research community. There are many intermediate factors that can affect a person between an intervention and a long-term outcome. This increases the noise in the measurement and leads to less definitive evidence about the effects of an intervention on long-term outcomes. Research into intermediate and long-term outcomes of interventions is a potential area for funding since it will generate more evidence for or against a given solution. In turn, this will lead to a consensus about an array of effective interventions which deliver results. This list is currently lacking and thus holding back this cause area from being funded.
Conclusion
Healthy fetal, newborn and infant development is critical for both short and long-term individual outcomes. Poor maternal nutrition, maternal stress, air quality, lack of education and an early environment not suited for healthy cognitive and emotional development lead to persistent negative outcomes in later life. Currently, there is a lack of a holistic approach to addressing the needs and development of young children. This is both due to a lack in consensus of effective interventions, and the difficulty in rolling them out at scale. However, given that we are likely underestimating the DALYs and QALYs caused by poor early development, and the potential intergenerational benefits of interventions, this is a cause area that should be considered for funding by Open Philanthropy.
References
Currie, J. (n.d.). Inequality before Birth Contributes to Health Inequality in Adults. Scientific American. https://doi.org/10.1038/scientificamerican1020-50
Currie, J., & Hyson, R. (1999). Is the Impact of Health Shocks Cushioned by Socioeconomic Status? The Case of Low Birthweight (Working Paper No. 6999). National Bureau of Economic Research. https://doi.org/10.3386/w6999 Golm, D., Maughan, B., Barker, E. D., Hill, J., Kennedy, M., Knights, N., Kreppner, J., Kumsta, R.,
Schlotz, W., Rutter, M., & Sonuga-Barke, E. J. S. (2020). Why does early childhood deprivation increase the risk for depression and anxiety in adulthood? A developmental cascade model. Journal of Child Psychology and Psychiatry, 61(9), 1043–1053. https://doi.org/10.1111/jcpp.13205
Financing Global Health | IHME Viz Hub. (n.d.). Retrieved August 4, 2022, from http://vizhub.healthdata.org/fgh
Lee, C. (2014). Intergenerational health consequences of in utero exposure to maternal stress: Evidence from the 1980 Kwangju uprising. Social Science & Medicine (1982), 119, 284–291. https://doi.org/10.1016/j.socscimed.2014.07.001
Ooms, G., Hammonds, R., Richard, F., & De Brouwere, V. (2012). The global health financing revolution: Why maternal health is missing the boat. Facts, Views & Vision in ObGyn, 4(1), 11–17.