Mothers live longer as child mortality declines

"The picture I was building in my mind was to think about what the population of mothers in the U.S. looked like in 1900," said Matthew Zipple, a Klarman Postdoctoral Fellow in neurobiology and behavior at Cornell University and author of "Reducing Childhood Mortality Extends Mothers' Lives," which published May 9 in Scientific Reports.

"It was a population made up of two approximately equal-sized groups: One was mothers who had lost children, and one was mothers who had not," Zipple said. "If we compare that to today, when child loss is mercifully so much less common, nearly all those women who had lost children are shifted into the non-bereaved category."

Using mathematical modeling based on Centers for Disease Control and Prevention (CDC) data, he calculated how the absence of bereavement affects the lifespans of present-day mothers in the United States. He estimates that the reduction in maternal bereavement adds, on average, a year to women's lives.

In the paper, Zipple cites several studies that causally link child death with increased risk of maternal death. The most comprehensive is a study of mothers in Iceland over a 200-year period, spanning a range of health care access and industrialization.

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

The study also helps set priorities for progress going forward, Zipple said. In many countries, child mortality rates today are similar to those in the U.S. in 1900. Investing in reducing childhood mortality everywhere helps not only the children, but whole communities.

"The child is the core of the community," Zipple said. "Protecting children from mortality has branching positive impacts that start with mothers but probably don't stop there."