Women who naturally conceive their last child after age 33 tend to live longer than those who have their final child by age 29, according to a new study by researchers at Boston University School of Medicine.
The study published on Wednesday in the journal Menopause, looked at the data from 462 women who were part of The Long Life Family Study, which included families with members who had lived long lives. The researchers compared the ages at which these women had their last child and how long they lived. Those who got pregnant naturally and successfully birthed their last child after age 33 were twice as likely to live to age 95 compared to those who had their last child by age 29.The average age of women at first birth has risen over the past four decades, according to the U.S. Centers for Disease Control and Prevention.
A growing number of U.S. women are now having children after age 35. The number of women undergoing fertility treatments such as in vitro fertilization to conceive later in life has also steadily increased. The current findings did not look into the life spans of women who used medical assistance to conceive.
“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,” study co-author Dr. Thomas Perls, a professor of medicine at BU, said in a medical center news release.
He believes that this may be a clue as to why 85 percent of people who live to 100 years or more are women, and only 15 percent are men.
The current findings suggest that prolonged fertility may be linked to a genetic marker for longevity, though a marker hasn’t yet been identified, according to Dr. Thomas Perls, a co-author of the study and a professor of medicine at Boston Medical Center and the Director of the New England Centenarian Study.
“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,” Perls said in a public statement.
The study findings held true even when researchers took into account lifestyle factors like smoking and obesity, which decrease the chance of having children naturally and are also considered age accelerators. Giving birth at older ages also means parenting younger children at an older age, a factor that seems disadvantageous to some women. “But for these women, it might not be all that bad,” Perls said.
Future research will investigate whether going through natural menopause at an older age is also a marker for slower aging.
“That will directly answer what we’re looking for, which is finding genetic variants that these women all have in common to explain why they age more slowly,” Perls said. “If we can better understand the biological pathways that these genes govern, we might find drugs that do the same things as the genes.”
Genetic variants that mean women remain fertile for longer may be the key, researchers said today.
Lead researcher Dr Thomas Perls, from Boston University Medical Center in the US, said the findings do not mean women should delay having children.
“Of course this does not mean women should wait to have children at older ages in order to improve their own chances of living longer,” said Thomas Perls, one of the researchers in a news release. “The age at last childbirth can be a rate of aging indicator. 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.”
The findings reveal the strong influence of genetics when it comes to longevity. More specifically, they indicate that women may be the driving force behind the evolution of genetic variants that slow aging and decrease risk for age related genes, since a longer living woman may be more likely to pass on her genetics to the next generation. The findings are actually consistent with previous studies that show the relationship between maternal age at birth of the last child and exceptional longevity.