Older Mothers, Longer Lives
Research shows giving birth later may be a marker for longevity
If you’re the only mother at your 40th high school reunion who still has a kid in high school, take heart.
A small but growing body of research suggests that women who conceived their children naturally at a relatively old age appear to live longer than their peers.
Not that getting pregnant at a so-called “advanced maternal age” will protect you from the scourges of middle and old age. Neither does deciding to complete your family while still in your 20s necessarily mean that you’re going to die younger. But the ability to conceive and deliver a baby in your mid- to late-30s or 40s appears to be a marker for longevity.
The most recent research comes from the Long Life Family Study, an international research project sponsored by the National Institute on Aging. The ongoing project involves 551 families, each with many members who’ve lived exceptionally long lives.
Longevity and Older Motherhood
In this study, scientists focused on 462 women who had conceived children naturally. They looked at the age at which the women delivered their youngest child and how old the women lived to be. The researchers found that women who had their last child after age 33 were twice as likely to live to 95 or older than women who had their last child by 29.
Women who had no children were excluded from this analysis, but, the authors note, only 70 women in the Long Life Family Study never had children.
“One hypothesis would be that women who had no children had diseases or environmental exposures that impaired fertility and decreased survival (e.g., diabetes, hypertension and autoimmune disorders),” the scientists wrote last month in the journal Menopause.
Their findings replicate research from the New England Centenarian Study. In 1997, Dr. Thomas Perls, the Boston University School of Medicine professor who directs the centenarians study, reported that women who conceived naturally and gave birth to a child after 40 were four times more likely to live to 100 than women who had their last child at a younger age.
Obviously, delivering a baby at age 34 isn’t as unusual as delivering a baby at age 41. The thing is, the people in the Long Life Family Study aren’t as old as those in the centenarian study, says Perls, one of the principal investigators in the former study.
While the centenarians, of course, are 100 or older, the oldest Long Life Family Study participants tend to be in their late 90s — so 33, not 40, ended up being the cutoff for comparison purposes, Perls says.
Perls has a personal interest in the connection between older age at childbirth and longevity. His wife, who’s now 57, was 41 when she delivered their last child, and her mother is about to turn 100. Her mother’s sister lived to 104 and her father lived to 97.
Learning From The Pioneers
The connection between older age at delivery and longevity has been traced back more than 300 years.
In 2009, University of Utah researchers published a study linking the two in pioneer women who lived in the 17th through 19th centuries. The Utah researchers analyzed high-quality genealogical records for Utahans born before 1870 and Quebec province residents born between 1670 and 1750. Both groups lived during a time of little or no effective birth control, so they were likely to keep having children until they couldn’t.
Utah women who delivered their last child at age 41 to 44 and Quebec women who had their last child between 42 and 44 ½ were 6 percent less likely to die during any given year past age 50 than women who last gave birth at a younger age. Women who were even older when they had their last baby were about 15 percent less likely to die during any given year past age 50.
Perls speculates that women who conceive naturally at an older age go through menopause later than other women. Getting 100-year-old women to remember when they went through menopause half a lifetime ago is difficult, to say the least, Perls says, but he’d like to ask that question of the oldest women in the family study as well as their daughters.
“I’m sure that’s true,” demographer Ken Smith, a professor of human development and family studies at the University of Utah, says of the connection between late childbirth and later menopause. “There are data to support that. Definitely, later menopause and later age of fertility are going to go hand in hand.”
It’s In The Genes
Smith was the lead author of the study of Utah and Quebec pioneers. He notes that, on average, all the women in the Longer Life Family Study lived long lives, no matter how old they were when they had their last child.
“It makes their finding all the more remarkable,” Smith says. “The two groups (longer- and shorter-lived) are not so different from each other. The fact they’re still able to see these differences, I think, just says we have something real here.”
Genetics play a significant role in determining longevity, Smith and Perls say. Smith’s group found that the brothers of the pioneer women who had children in their 40s also had a reduced chance of dying, but their wives did not. This suggests that genes, far more than environmental factors, contribute to prolonged fertility and longevity.
The Long Life Family Study participants, Perls says, represent “a very powerful way of discovering what those genetic variants might be.”
Rita Rubin is a former USA Today medical writer who now writes about health and science for publications including Next Avenue, WebMD and NBCNews.com.