Infant mortality

• 1. Introduction

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  Infant mortality is, at its simplest, the death of a child before its first birthday. Yet behind that bare definition lies a story that cuts across every society on earth, shaping how nations measure their own progress and exposing fault lines of poverty, race, and political will.

  In 1990, roughly 8.8 million infants younger than one year died globally. By 2021, that number had fallen to 5 million. A reduction of that scale in a single generation represents one of the most significant shifts in modern public health. And yet 5 million children still do not reach their first birthday every year.

  The infant mortality rate, known as the IMR, is the number of deaths of infants under one year per 1,000 live births. That ratio is deceptively simple. Researchers at Biotechnology and Health Sciences, working across 135 countries over 11 years, found that education levels and life expectancy are the leading indicators of where a country's IMR will fall. The continent of Africa recorded the highest rate of any region in that study, at 68 deaths per 1,000 live births.

  The global rate in 2011 was 51 deaths per 1,000 births for children under five. Singapore recorded the lowest rate at 2.6. Sierra Leone recorded the highest at 185. A factor of roughly 67 separates Monaco, with the lowest IMR of 1.80, from Afghanistan, where the rate stands at 121.63. What explains that chasm, what drives it, and what can close it are the questions this documentary will explore.

• 2. The Main Killers

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  Three causes account for the lion's share of infant deaths in the United States and many other countries: conditions linked to preterm birth, congenital anomalies, and sudden infant death syndrome, or SIDS. In North Carolina between 1980 and 1984, a study found that prematurity alone accounted for 37.5% of infant deaths, with congenital anomalies at 17.4% and SIDS at 12.9%.

  Preterm birth is defined as delivery before 37 weeks of gestation, against a full-term benchmark of 40 weeks. The subdivisions run from mild preterm (32 to 36 weeks), to very preterm (28 to 31 weeks), to extremely preterm, meaning before 28 weeks. The earlier the birth, the steeper the risk. Between 1990 and 2010, prematurity ranked as the second-leading cause of mortality worldwide for newborns and children under five. In 2010, the overall preterm birth mortality rate was 11.1%, with 60% of all preterm births concentrated in low- to middle-income countries in sub-Saharan Africa and South Asia. For infants born before 28 weeks of gestation in those low-income countries, the survival rate is 10%. In high-income countries, it is 90%.

  SIDS presents a different kind of challenge: its exact cause remains unknown. The Centers for Disease Control and Prevention identify SIDS as the leading cause of death in infants aged one month to one year. Researchers developed a "triple-risk model" pointing to three overlapping factors: smoking while pregnant, the age of the infant, and stress from conditions such as prone sleeping, co-sleeping, or overheating. A campaign called Back to Sleep, which advised parents to place babies on their backs rather than their stomachs, lowered the SIDS death rate by 50%.

  Congenital malformations, present at birth, include conditions such as cleft lip and palate, Down syndrome, and heart defects. In the Caribbean and Latin America in the 1980s, congenital malformations accounted for only 5% of infant deaths, while malnutrition and infectious diseases accounted for 7% to 27%. In the United States, however, congenital malformations became a more prominent cause, with a 39% decline in infant deaths from heart conditions recorded between 1979 and 1997 as medical care improved.

• 3. Weight, Nutrition, and Infection

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  Low birth weight makes up 60 to 80% of the infant mortality rate in developing countries. The New England Journal of Medicine put the disparity in stark terms: infants weighing 2,500 grams or less face rapidly increasing mortality as weight falls, and most infants weighing 1,000 grams or less die. Compared with normal-birth-weight infants, those with low birth weight are almost 40 times more likely to die in the neonatal period. For infants with very low birth weight, the relative risk of neonatal death is almost 200 times greater.

  Malnutrition compounds these risks. An estimated 3.5 million children die each year as a result of childhood or maternal malnutrition, with stunted growth, low body weight, and low birth weight accounting for about 2.2 million of those deaths. In Africa, the number of stunted children has risen. Asia holds the most children under five suffering from wasting. Malnutrition weakens the immune system, raising death rates from malaria, respiratory disease, and diarrhea.

  Infectious disease claims lives through several overlapping routes. Bacterial infections of the bloodstream, lungs, and the brain's covering account for 25% of neonatal deaths worldwide. Acute respiratory infections such as pneumonia, bronchitis, and bronchiolitis account for 30% of childhood deaths, with 95% of pneumonia cases occurring in the developing world. Diarrhea ranks as the second-largest cause of childhood mortality globally, while malaria causes 11% of childhood deaths and measles is the fifth-largest cause. Seven out of ten childhood deaths are due to these infectious diseases combined.

• 4. Race, Stress, and Structural Harm

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  In the 1850s, the infant mortality rate in the United States was estimated at 216.8 per 1,000 white babies and 340.0 per 1,000 African American babies. Rates have fallen dramatically since then, but a persistent gap has never closed. Non-Hispanic Black women have an infant mortality rate of 11.3; for white women the rate is 5.1. African American infants are more than twice as likely to die in their first year of life than white infants.

  Socioeconomic factors are a real part of the story but cannot fully explain the disparity. The poverty rate for Black Americans is 24.1% and for Latino Americans is 21.4%, yet the infant mortality rate of Latinos is much closer to that of white women than to that of Black women. Foreign-born African immigrant women, coming from a completely different social context, do not share the elevated IMR experienced by American-born Black women, which argues against purely genetic explanations.

  Tyan Parker Dominguez at the University of Southern California argues that African American women experience stress at much higher rates than any other group in the country. Stress produces hormones that can induce labor, and premature birth is one of the leading causes of infant death. For lower-class Black women, that stress stems from an unstable family life and chronic worry over poverty; for middle-class Black women, battling racism can be an extreme stressor.

  Arline Geronimus, a professor at the University of Michigan School of Public Health, calls the underlying process "weathering." She argues that constantly dealing with disadvantage and racial prejudice causes Black women's birth outcomes to deteriorate with age, so that older Black women face compounding pregnancy complications beyond economic factors. Mary O. Hearst, a professor at Saint Catherine University, adds that residential segregation contributes to high rates regardless of a Black mother's socioeconomic status, given its political, economic, and health implications. A study in North Carolina found that white women who did not complete high school had a lower infant mortality rate than Black college graduates.

• 5. Environment and War

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  Organic water pollution is a better predictor of infant mortality than health expenditures per capita. Water contaminated by animal waste carries a host of parasitic and microbial infections, and low-income areas tend to have the weakest plumbing infrastructure to manage it.

  Air pollution reaches infants in two distinct ways: through the pregnant parent's exposure during gestation and through the air the newborn breathes after birth. Carbon monoxide, colorless and odorless, is especially dangerous to infants because of their immature respiratory systems. Second-hand smoke killed nearly 900 infants in the United States in 2006 alone. Smoking less than one pack of cigarettes per day during pregnancy raised the risk of infant mortality by 25% compared with non-smoking mothers having their first birth. Smoking one or more packs per day raised that risk by 56%.

  The burning of inefficient fuels doubles the rate of acute respiratory tract infections in children under five. Air pollution is also specifically associated with SIDS in the United States during the postneonatal stage.

  War collapses these risks to a critical point. During the Yugoslav Wars in the 1990s, Bosnia experienced a 60% decrease in child immunizations, leaving populations vulnerable to diseases that had been under control. The number of premature babies born in Bosnia increased, and average birth weight decreased. Preventable diseases can quickly become epidemics during conflict. For people who become pregnant as a result of rape during war, challenges are multiplied: studies suggest they are more likely to experience infant death, with causes ranging from physical trauma to psychological effects that can complicate adjustment to society. Many who became pregnant by rape in Bosnia were isolated from their hometowns, making life after childbirth exponentially more difficult.

  A 2009 study found that economic slowdowns reduce air pollution, which can lower infant mortality rates in the short term. In the late 1970s and early 1980s, the recession's effect on air quality was estimated to have saved around 1,300 US babies. But deep recessions, in which per capita GDP drops by 15% or more, reverse that pattern and increase infant mortality rates.

• 6. Counting the Dead

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  How a country counts births and deaths shapes its infant mortality statistics as much as the actual number of deaths. The World Health Organization defines a live birth as any infant demonstrating independent signs of life, including breathing, heartbeat, umbilical cord pulsation, or definite movement of voluntary muscles. Germany uses this definition but excludes muscle movement as a sign of life. France and Japan count only cases where an infant breathes at birth, which lowers their reported IMR and raises their rates of perinatal mortality. The Czech Republic and Bulgaria apply even stricter criteria.

  Until the 1990s, Russia and the Soviet Union excluded extremely premature infants from both live birth and infant death counts if the infants failed to survive at least seven days. These were infants born weighing less than 1,000 grams, before 28 weeks of gestation, or less than 35 centimeters in length. Although such infants typically accounted for only about 0.5% of all live-born children, their exclusion led to an estimated 22 to 25% lower reported IMR.

  In northeastern Brazil, a structural problem runs in the other direction. Infant births and deaths are frequently never recorded at all, because poor rural families cannot afford the lodging and travel costs required to report to registration offices. Government statistics there consistently understate mortality. An ethnographic study found that "popular death reporters," including grave-diggers, midwives, coffin builders, and priests, provided more accurate death counts than official registries or household surveys combined.

  Political incentives have also distorted counts. One governor in Ceara built a presidential campaign around reducing the infant mortality rate during his term, creating direct pressure to report lower numbers. In some regions of Russia, infant deaths occurring in the 12th month of life were statistically transferred to the 13th month, removing them from the infant mortality count entirely.

  When new medical centers open in areas with poor services, reported IMRs often rise rather than fall, at first. This is because new facilities register deaths that previously went unrecorded. The demographer Ansley Coale identified a related pattern in Hong Kong and Japan, where suspiciously high ratios of reported stillbirths to infant deaths in the first 24 hours after birth suggest that female infant deaths are being misclassified as stillbirths.

• 7. What Can Change

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  More than 60% of deaths of children under five are considered avoidable with low-cost measures: continuous breastfeeding, vaccinations, and improved nutrition. The evidence behind each of these is specific and well-documented.

  Following the introduction of the pneumococcal conjugate vaccine in the United States in 2000, studies published in 2004 found a 57% decline in invasive penicillin-resistant strains of the disease and a 59% reduction in multi-drug resistant strains. Among children under two, the reduction reached 81%. Immunizations given in accordance with recommended guidelines have also been shown to reduce the risk of SIDS by 50%.

  Adding one physician per 10,000 people carries a potential reduction of 7.08 fewer infant deaths per 10,000 in that population. In high-risk areas such as sub-Saharan Africa, increasing women's educational attainment has been shown to reduce infant mortality by about 35%. Training community health workers in diagnosis, treatment, malnutrition prevention, and referral services has reduced infant mortality in children under five by as much as 38%.

  Home-based water chlorination, filtration, and solar disinfection could reduce diarrhea cases in children by up to 48%. Hand washing with soap, promoted by UNICEF before eating and after using the toilet, significantly reduces deaths from diarrhea and acute respiratory infections. Salt iodization has reduced negative birth outcomes linked to low iodine levels. Folic acid supplementation, now mandatory in the food supply of many countries, has significantly reduced the occurrence of spina bifida in newborns.

  The United States ranks 173rd out of 227 entities in the CIA World Factbook's 2024 ranking, with a rate of 5.1 deaths per 1,000 live births, despite conventional births averaging US$9,775 and preterm births costing an estimated $51,600 per child, with a total yearly national cost of $26.2 billion. The Best Babies Zone program, based at the University of California, Berkeley, is one concrete attempt to close that gap by addressing structural causes of poor birth outcomes in communities disproportionately affected by infant mortality, using community-generated solutions rather than top-down clinical mandates.