Did you, or will you, have a baby after the age of 33? Then you might live much longer than the average woman, or so say researchers. According to research by Thomas Perls, director of the New England Centenarian Study (NECS), women who are able to have children after the age of 33 have a greater chance of living longer than women who had their last child before the age of 30.
And it wasn’t a small difference; women who had their last child after the age of 33 doubled their chances of living to age 95 or older compared with women whose last child was born before their 30th birthday.
The study, scheduled for print publication in Menopause: The Journal of the North American Menopause Society in January 2015, also provided evidence that the genetic variations that go into making a woman fertile longer may also increase her chances of having an unusually long life spans, researchers say.
“The natural ability to have a child at an older age likely indicates that a woman’s reproductive system is aging slowly, and therefore so is the rest of her body,” said Perls.
Unlike some aging and fertility research, which focuses on a woman’s age at first birth, this study looked at when women had their last child. Explained Perls, a Professor at Boston University School of Medicine: “The age at last childbirth can be a rate of aging indicator.”
This isn’t the first research out of the NECS highlighting the connection between a woman’s age when she last gives birth and increased longevity; a previous study found that women who gave birth to a child at or after 40 had four times the chance of living to 100 than women who were younger when they had their last child.
Perls stressed that his research does not mean that if you wait longer to have children, you’ll live longer. And longevity should not be used as a reason to postpone having children.
For one thing, women’s fertility peaks in her 20s and declines precipitously after the age of 30. According to current research statistics, your chance of having a baby (without drugs or IVF) within a year is 75 percent at age 30, 66 percent at 35, and just 44 percent at 40. If you give yourself four years of trying, your odds increase to 91 percent at age 30, 84 percent at 35, and 64 percent at 40.
Perls’ Boston University research team analyzed data from the Long Life Family Study (LLFS), a co-effort by BU and three other universities that studies a cohort of 551 families in which many members live exceptionally long lives. From this group, researchers used a pool of 462 women for whom they knew the age at last birth and age at death.
But let’s take a look at a couple of caveats, here. First, the women included in this study were already from families with a propensity to be unusually long-lived. I would like to see the researchers tease out this distinction, and make a case for how we would know the conclusions can be generalized to apply to all women.
Then there’s the issue of association rather than causation. Sociological data show that women who have children at a later age tend to be better off and better educated, factors that are associated with making healthier lifestyle choices as well.
According to Perls, the study results also suggest that the link between extended fertility and longevity may be driving the evolution of genetic variants that slow down aging and prolong life.
How? “If a woman has those variants, she is able to reproduce and bear children for a longer period of time, increasing her chances of passing down those genes to the next generation,” said Perls. He noted that women make up 85 percent of who live to age 100, while just 15 percent of centenarians are men.
(Courtesy of Forbes Magazine)