From the press release:
Researchers found that women who had their first child outside of marriage described their health as poorer at age 40 than did other moms.
About 40 percent of all births in the United States now occur to unmarried women, compared to less than 10 percent in 1960, Williams said. That suggests there will soon be a population boom in the United States of single mothers suffering middle-aged health problems.
Moreover, the study suggests that later marriage does not generally help reverse the negative health consequences of having a first birth outside of marriage. This calls into question the value of government efforts to promote marriage, among low-income, single mothers, at least in terms of their consequences for these women’s health.
In one analysis, Williams and her co-authors used a subset of data from the National Longitudinal Survey of Youth on 3,391 women and a second analysis involved data on 1,150 women. By 2008, they had data on marriages and other unions for a 29-year period, and measures of health and well-being taken when the women were 40.
In general, the results showed that unwed mothers reported poorer health at age 40 than did other mothers. But there were several notable differences between racial and ethnic groups.
Most notably, Hispanic women who had a first child outside marriage did not have the same negative health consequences at age 40 that white and black women did. The researchers suspect that it has to do with the fact that when Hispanic women have a child out of wedlock, it is more likely to occur in a long-term cohabiting relationship that resembles marriage.
Hispanic single mothers may also be a part of larger and more close-knit family networks than single moms from other racial and ethnic groups, which can provide support that protects their health and helps them cope.
It was beyond the scope of this study to determine why unwed mothers in general had poorer health than others. But other research suggests it may be related to the high levels of stress and the poor economic conditions faced by single moms.