The study found that 1 in 3 women surveyed from the US had been a single mother before reaching the age of 50.
The study, published in the Journal of Epidemiology & Community Health, analyzed data from 15 different countries and found that the health risks appeared to be greatest for single mothers in the US, England, Denmark and Sweden.
According to the authors of the study, single motherhood is associated with an increased risk of multiple health problems, including adverse cardiovascular episodes, poor mental health and increased mortality.
While many studies have focused on the immediate associations between single motherhood and health, few have investigated how single motherhood during early and mid-adulthood impacts upon health in later life.
Additionally, very few studies have examined whether these associations between health and single motherhood are consistent across different countries. The authors were keen to address this issue on account of differences in how single motherhood is perceived across the world.
"Single motherhood is associated with poverty in most societies, but more so in the USA than in Europe," the authors explain. "This may lead to different mechanisms of selection into lone motherhood between countries. Particularly in Southern European countries, strong social and family networks may offset some negative effects of single motherhood."
For the study, the researchers analyzed data for 25,125 women aged over 50 who had participated in one of three nationally representative surveys. These were the Health and Retirement Study in the US, the English Longitudinal Study of Ageing in England and the Survey of Health, Ageing and Retirement in 13 other European countries.
Each participant was asked questions about their childbearing and marital status, along with questions about their capacity for routine daily activities such as maintaining personal hygiene, and instrumental daily activities such as driving. All participants were also asked to rate their own overall health.
Participants were identified as single mothers in any year when they had children under the age of 18 and were not married. All participants were asked to report all children's birth or adoption dates, as well as specify the beginning and ending dates of any marriages.
Study findings may indicate 'cycles of disadvantage'
The researchers found that 1 in 3 women from the US surveyed had been a single mother before the age of 50. In comparison, around 1 in 5 women surveyed in England and West European countries, around 4 out of 10 surveyed in Denmark and Sweden and around 1 in 10 women in Southern Europe reported having been a single mother.
In every country, single mothers were frequently younger, had less money and were less likely to marry than women who remained married during motherhood. On average, single mothers from the US and England also had lower levels of education.
Women who had been single mothers for any period were more at risk of physical disability and poor health in later life in comparison with women who had raised children with a partner. This association was greatest among single mothers in the US, England, Denmark and Sweden.
The following women were at particular risk according to the study's findings:
- Those who became single mothers before the age of 20
- Those who became single mothers through divorce
- Those who were single mothers for 8 or more years
- Those who raised two or more children.
According to the researchers, their findings could indicate selection and causation in "cycles of disadvantage." For example, the risk of single motherhood is increased by poverty, which may reflect previous health disadvantages.
"Being a lone mother may hamper women's abilities to gain education, accrue careers and accumulate income, also leading to poorer health," the authors add.
The existence of strong social support in certain countries may explain why the associations were not as strong in some geographic regions. The authors state that in regions such as Southern Europe, the cultural emphasis placed on family solidarity means that single motherhood is not associated with any increased health risks.
"Findings add to the growing recognition that single motherhood may have long-term health effects on mothers," conclude the authors.
"As prevalence of single motherhood is on the rise across the developed world, social policies that protect women in vulnerable family situations may help improve population health and reduce health disparities as women age."