Centenarians are four times as likely to have had babies in their 40s, according to research. The study from Harvard Medical School suggests that a woman’s ability to have children in her 40s may be an indicator of slower aging, thus giving her the potential for a very long life.

Only 2 percent of births occur to women in their 40s, and apparently they all live in Hollywood. Or so it would seem from celebrity headlines.

Kelly Preston, wife of John Travolta, had her third child recently at 48. Holly Hunter had twins at age 47. Twins were born to Geena Davis at 48 and Jane Seymour at 45 when she gave birth. Supermodel Cheryl Tiegs bested them all by giving birth to twins at 52.

Halle-Berry-baby-bump
Halle Berry

But the poster mom for advanced-age birth is Halle Berry, who had two children in her 40s. The 48-year-old actress gave birth to her son Maceo earlier this year, and her daughter Nahla in 2008.

Related: Coffee a Latte Risk for Moms

Maybe it is something in the California water. Wait, there isn’t any water in California. Then what is it?

It’s in vitro for some, good genes for others. For the latter, those same good genes that allow some to conceive at a time in life when fertility has flatlined for most women also predict a longer life.

Kelly Preston

The analysis, published in the prestigious journal Nature, looked at reproductive records for two groups of women born in 1896. Of the women who had died in their 70s, only 5.5 percent had given birth in their 40s, compared to 19.2 percent of the women who’d lived well into their 100s. Since the women lived largely before modern fertility treatments, the findings speak to a longevity-fertility link in cases of unassisted conception.

“Women who age more slowly — i.e., were able to conceive in their 40s — lived longer in this study,” study co-author Dr. Ruth Fretts told LifeZette. “But it doesn’t suggest that giving birth later extends longevity.”

Moreover, these women who were born in the 19th century reflect a very different group than women conceiving later in life today.

Who do you think would win the Presidency?

By completing the poll, you agree to receive emails from LifeZette, occasional offers from our partners and that you've read and agree to our privacy policy and legal statement.

“What this study looked at was a natural cohort. Today we are, by and large, looking at an unnatural cohort of pregnancies that happen due to fertility management,” Fretts said.

“What this study looked at was a natural cohort. Today we are, by and large, looking at an unnatural cohort.”

Fretts, an OBGYN clinician at Harvard Vanguard Medical Associates, is also an assistant professor at Harvard Medical School. She said she wouldn’t want her study results, or celebrity births to women in their 40s, to provide false hope.

“The fertility rate tanks at 38-39,” she said. “So the rate of someone getting pregnant after 44 is either by great luck or fertility management. My area of focus is adverse pregnancy outcomes and stillbirths, both of which are more likely as women get older.”

Related: Born Yesterday

Another more recent study from the University of Utah suggests a genetic component — namely a 15 percent lower mortality risk (post 50 years of age), for women who gave birth after age 45. And if you’re a man whose sister gave birth later in life, it suggests you and she come from hearty genetic stock.

Cheryl Tiegs
Cheryl Tiegs

“This may be a select group of women that overall may have better health and/or less predisposition to medical/genetic conditions,” Dr. Anita Singh, the director of Lifestart Fertility Center, said of the study.

In her Agoura Hills, California, practice, Smith works with couples seeking to conceive. “Every year a women ages her fertility declines,” she said. “Leading a healthier lifestyle will not extend your ‘biological time clock’ or increase your fertility or reproductive years.”

That said, there are plenty of things that will decrease a woman’s fertility, she said. For example, women who smoke have reduced fertility. Women who are excessively lean or overweight also have reduced fertility, Smith said.

“Women who have children later in life are less likely to have suffered from cancer or have lifelong medical conditions such as (high blood pressure) or diabetes, so they live longer. Also, women who have children later in life probably have had more than one child. Women who have had children have a lower risk for health conditions, including ovarian and breast cancer, again leading to living longer.”

This article was originally created by the Dole Nutrition Institute, with additions and updates by LifeZette.