Lower-Income Families Face Worse Birth Outcomes as Low Birthweight Gap Grows
- New research indicates that babies born to lower-income families in the United States are more likely to be born too early or too small, with disparities in low...
- The study, published in JAMA Pediatrics, analyzed 380,000 births across the United States between 2012 and 2022.
- Researchers found that mothers with lower incomes experienced worse birth outcomes across all newborn-health metrics.
New research indicates that babies born to lower-income families in the United States are more likely to be born too early or too small, with disparities in low birthweight widening over the last decade.
The study, published in JAMA Pediatrics
, analyzed 380,000 births across the United States between 2012 and 2022. It is among the few studies to establish a direct link between maternal income and a baby’s health at birth.
Researchers found that mothers with lower incomes experienced worse birth outcomes across all newborn-health metrics. While the gap between lower- and higher-income families remained consistent for most metrics over the 10-year period, low birthweight emerged as a significant and growing exception.
The Growing Gap in Low Birthweight
Low birthweight serves as a key indicator of overall infant health. According to the study, the prevalence of low birthweight rose more sharply among lower-income families than among those with higher incomes.
For families classified as low-income—defined by the authors as those living below 200% of the federal poverty level—the rate of low birthweight increased from 7.2% in 2012 to 9.4% in 2022.
In comparison, higher-income mothers saw only a slight increase in low birthweight rates, moving from 5.7% to 6.3% during the same period.
The growing gap in low birthweight was surprising and especially concerning, particularly because it was largely driven by increasing rates among the lower-income families
Emily Dore, postdoctoral fellow at Harvard T.H. Chan School of Public Health and lead author of the study
Broad Impacts on Newborn Health
The study noted that approximately 37% of the mothers involved were classified as low-income. These women faced higher risks across nearly every measured metric of newborn health, including:
- Higher rates of preterm births
- Shorter overall pregnancy durations
- Higher rates of low birthweight
- Lower average birthweights overall
Preterm births, which occur when a baby is born before 37 weeks of pregnancy are completed, are a leading cause of infant illness and death. Babies born underweight or too early face increased risks of serious health problems, lifelong developmental challenges, and developmental delays.
Social Determinants of Health
The findings suggest that financial strain impacts a baby’s health from the beginning of development. Researchers argue that these outcomes are shaped by social and structural determinants rather than random distribution.
Megan Reynolds, a sociologist at the University of Utah and coauthor of the study, emphasized that health care only explains a small portion of these health disparities.
Moms are exposed to all kinds of conditions that affect their health before they even get to a doctor. Worrying about housing, food access—the stress from financial hardship gets under the skin and causes the body to malfunction
Megan Reynolds, sociologist at the University of Utah
While programs providing food assistance and income support can help offset these hardships, the researchers noted that the generosity of social safety nets varies by state and may be insufficient to close the gap.
Data Challenges and Policy Implications
The researchers relied on the Center for Disease Control’s Pregnancy Risk Assessment Monitoring System (PRAMS), a national survey that has tracked maternal and infant data since the 1980s. Reynolds described the dataset as a treasure
because it captures both the circumstances surrounding birth and the birth outcomes themselves.
However, the study highlights a critical risk to future research: the CDC PRAMS office was shuttered indefinitely in the spring of 2025 and faces the risk of disappearing entirely.
The authors of the study, which included contributions from Daniel Collin and Rita Hamad of the Harvard School of Public Health, hope the data will encourage policymakers to adopt a social-policy-as-health-policy philosophy
.
Emily Dore stated that interventions aimed at reducing poverty, such as anti-poverty policies, may be especially necessary at this time to ensure babies from all socioeconomic backgrounds have the opportunity to live long, healthy lives.
The research was supported by grants from the National Institutes of Health.