(Newser) – Women who are able to get pregnant naturally and give birth in their mid-30s and after tend to live longer than other women, a new study suggests. Specifically, Boston researchers found that women who gave birth after age 33 were twice as likely to live to 95 than women who were done having kids at 29, reports Medical Daily. So what kind of effect should this have on a young couple's family planning? Not much, the co-author of the study in the journal Menopause tells the Boston Globe. “Women shouldn’t delay child-bearing based on this study,” says Thomas Perls. But he hopes it will get people to stop second-guessing women who become pregnant in middle age.

"Critics say they’ll be too old to care for their teens or help raise their grandchildren," says Perls, "but I would wager that these women are aging exceptionally well.” One caveat: The extra longevity doesn't apply to women who use IVF or other technologies to get pregnant. So what's going on? Researchers think that women who are able to get pregnant and conceive at older ages have "genetic variants" that slow down their own aging, reports Counsel & Heal. What's more, by reproducing longer, they have a better chance of passing along those genes. "This possibility may be a clue as to why" many more women than men live to hit the century mark, says Perls. (Click to read about a woman who gave birth via IVF using her own 46-year-old egg.)

