Reducing infant mortality extends mothers' lives

Significant declines in infant mortality in the 20th century added a full year to women's life expectancy, according to a new study.

"I imagined what the population of mothers in the United States looked like in 1900," said Matthew Zipple, a doctoral student in the Klarman program in neurobiology and behavior in the College of Arts and Sciences and author of the paper "Reducing Infant Mortality Extends Mothers' Lives," published in Scientific Reports.

"This population consisted of two roughly equal-sized groups: one group of mothers who had lost children, and the other of mothers who had not," Zipple said. "If you compare that to today, when child loss has become much less common, almost all of these women who have lost children have now moved into the category of non-grievers."

Several studies show that mothers are more likely to die in the years after a child's death, Zipple said. This effect does not occur in fathers.

Using mathematical modeling based on data from the Centers for Disease Control and Prevention (CDC), he calculated how the absence of grief affects the life expectancy of modern mothers in the United States. He estimated that reducing maternal grief adds an average year to women's life expectancy.

As a doctoral student researching links between maternal fitness and offspring, Zipple discovered a pattern of maternal death following offspring death in non-primates. In animals, this effect was explained by the fact that mothers were in poor health and less able to care for their offspring.

But in humans, the same sequence of events—the death of the offspring followed by the death of the mother—has been interpreted differently in studies with a human focus. Instead, epidemiologists and public health researchers conclude that the physical and psychological costs of the trauma of losing a child make mothers more likely to die.

In the article, Zipple cites several studies that causally link the death of a child to an increased risk of maternal death. The most extensive study is a study of mothers in Iceland over a 200-year period, covering varying levels of access to health care and industrialization. It controls for genetics, comparing siblings, and shows that grieving fathers are no more likely to die than non-grieving fathers in the years after a child's death.

Another study in Sweden shows that mothers are at higher risk of dying on and around the anniversary of a child's death than at other times. According to various studies, common causes of death among grieving mothers include heart attack and suicide.

"There is a huge peak in mortality risk immediately during the week around the anniversary," Zipple said. "It is difficult to come to any conclusion other than that it is caused by the memory of this event."

Life expectancy for women after age 15 increased by about 16 years between 1900 and 2000, Zipple found from CDC data used in the study. His calculation attributes one year, or about 6% of this increase, to the significant decline in child mortality over the course of the 20th century.

"One of the most horrific things you can imagine is the loss of a child. And we've been able to reduce the incidence of that in our society by more than 95%. It's amazing. It's something to celebrate," Zipple said.

p>

"It's easy to lose sight of the progress that happens over a century because it extends beyond the lifetime of any one person. But this increase in overall life expectancy over the last 100 years has improved people's living conditions and experiences in ways never before."

Priorities for the future

The research also helps set priorities for improving the future, Zipple said. Many countries today have infant mortality rates similar to those in the United States in 1900. Investing in reducing child mortality everywhere helps not only children, but entire communities.

“The child is the core of the community,” Zipple said. "Protecting children from mortality has ramifications of benefits that begin with, but likely do not end with, mothers."