US trend toward older maternal age increases racial inequality in negative birth outcomes according to a new study

June 20, 2023

Contact: Jon Meerdink ([email protected])

ANN ARBOR — Black and white babies are being born too small and unhealthy at higher rates than they were 30 years ago and the racial inequity of these poor birth outcomes has increased over the same span. According to a new paper, increased maternal age is a significant contributing factor: more U.S. women are waiting until their thirties to have children, an age at which all mothers experience some depletion of reproductive capacity, while Black and working-class white women have suffered structurally induced threats to their health that increase the odds of an unhealthy pregnancy.

The paper is the work of Arline Geronimus, Sc.D., Professor of Health Behavior & Health Education at the University of Michigan School of Public Health and Research Professor at the Population Studies Center at the Institute for Social Research. In the paper, published this month in Health Affairs, Geronimus explores three decades of national data on U.S. infants. The findings confirm absolute rates of very low birth weight (defined as a birth weight of 1500 g, or about 3.3 pounds), increased.

“This is a distressing public health development as many infants born that small don’t survive, and those who do are at increased risk of developmental disabilities that can be lifelong.

Geronimus further noted how very expensive this trend is, both in terms of trauma to the family as the newborn needs to spend a prolonged time in neonatal intensive care rather than coming home, and in terms of health care costs both to the family and the nation. The increase in poor infant health occurred during a time period where eliminating racial inequities in infant health has been an explicit and high-priority national public health objective. However, inequities still grew.

“To improve policy and practice in support of infant health we need to consider the pregnancy risks associated with maternal age not simply as reflecting a universal developmental process from reproductive immaturity to maturity to menopause, but also as contingent on the different lived experiences of more or less advantaged American women from their birth to their age at and during pregnancy,” Geronimus said.

The paper’s findings are consistent with other work Geronimus has done on a phenomenon she’s termed “weathering,” that provides evidence that the health of marginalized women deteriorates more quickly than others during their reproductive and working ages, especially among Black women.

“This is not due to any essential biological differences between Black and white women — or between affluent compared to working class or poor white women — but to the disparate impacts of structural racism, cultural oppression and economic exploitation on their bodies,” Geronimus said.

Geronimus analyzed data on a mother’s first birth from 1989 to 2019, using bridged race categories to identify the races of the mothers involved and taking account of maternal socioeconomic characteristics to study trends in very low birth weight, neonatal mortality, and infant mortality rates among non-Hispanic Black and white mothers.

“We should start looking at these problems through a weathering lens rather than a universal reproductive, developmental lens,” said Geronimus. “We should realize that people in different positions in our social structure with different access to resources and different degrees of exposure to environmental toxins, psychosocial stressors and material hardships will not fit the same age patterns of health. Twenty does not equal 20 and 30 is even less likely to equal 30 when comparing the health of more and less disadvantaged groups.”

The full paper is available online and in the May edition of Health Affairs. For more on related trends concerning race and health outcomes, Geronimus’ book, Weathering:The Extraordinary Stress of Ordinary Life in an Unjust Society, is available via Hachette Book Group.

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