A new study found that single mothers in certain countries had a higher risk for health problems as they get older.

Single motherhood during early or mid-adulthood can produce poorer health for those mothers later in life, according to a new study from an international group of researchers.

The health effects vary depending on where the mothers live. Researchers found the risk was greatest in England, the United States, and Scandinavia. It was less serious in western, eastern, and southern European countries.

The new study, from researchers across the globe ranging from the Harvard Center for Population and Development Studies to Tsinghua University in Beijing to the London School of Economics and Political Science, was published in the Journal of Epidemiology & Community Health

The study was based on the responses from more than 25,000 women who are 50 years old or older. They answered questions about childbearing, marital status, lifestyle, and health.

From the answers, researchers found that single motherhood in early adulthood or parenting without a marital partner increased the risk of health problems such as decreased self-rated health, cardiovascular risk, and poorer mental health.

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When and how a mother became a single mother is important. Women who were single mothers before the age of 20, single as the result of divorce, were single parents for eight or more years, or had two or more children, were at particular risk of poorer health later on, according to the study.

Single motherhood is defined as having a child under the age of 18 years without a marital partner. One in three mothers surveyed in the United States had been a single mother before the age of 50, compared to one in five in England and western European countries, one in four in Denmark and Sweden, and one in 10 in southern Europe.

The association with poorer health is in part due to the lack of available support and social services for single mothers, but researchers were surprised to find out that even in countries where there was more robust aid, poorer health findings were consistent.

For example, U.K. single women did about the same as single women in the United States.

“We had anticipated that single mothers in the United States would do poorly given that so many single moms are poor or low-wage workers and that the United States lacks most basic social protections for single mothers compared to other countries,” said study co-author Dr. Lisa Berkman, a professor of public policy and director of the Harvard Center for Population and Development Studies.

Scandinavian women have many forms of social protections, but in spite of maternity leave and basic anti-poverty programs, single women still had a tough time there.

“We suspect that the basic social protection was still very helpful to them but not sufficient to protect these women,” Berkman said. “They still tend to be poorer than married mothers and it may be that their work situations were challenging and that their extended families were not as supportive as those in southern European countries.”

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Another aspect working against single mothers is that they tend to be younger, less financially secure, and in the United States and England, less educated.

The researchers hope this type of research will be replicated and examined in younger and middle-aged women who are single mothers. If the findings are similar, and it turns out that single motherhood is associated with poorer health for different age brackets, intervention may be needed.

“Our findings suggest that single mothers may benefit from a wide range of social, economic, and health protection policies,” Berkman said. Protection can range from programs that mitigate poverty, and enable single mothers to get a job and participate in the workforce with some flexibility to take care of their families. In addition, adequate preventive services would likely be helpful as well.”

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