Children born to mothers who are stressed during pregnancy may become adults with prematurely aged cells.

A comparison of 94 young adults found those subjected to prenatal stress tended to have white blood cells with shorter telomeres, the protein caps that prevent chromosome tips from fraying when cells divide.

Whether telomere shortening is a cause of aging’s ravages, or if age-related deterioration causes telomeres to shorten, isn’t known. Either way, shortening is linked to chronic disease risk and diminished longevity.

White blood cells of prenatally stressed adults “had aged the equivalent of approximately 3.5 additional years,” wrote researchers led by University of California, Irvine fetal development specialists Pathik Wadhwa and Sonja Entringer in an August 2 Proceedings of the National Academy of Sciences study.

Telomere length comparison in 94 25-year-old adults born to stressed or unstressed mothers. Wadhwa et al./PNAS

Many studies have linked health problems to physical and psychological stresses, response to which wears down our body’s immune and metabolic systems. Studies have also linked adult health to maternal stress: A mother’s stress responses are passed on to her infants, making them more vulnerable to chronic diseases.

Connecting mother, fetus, and ultimately baby in stress are a variety of mutually inexclusive, as-yet-partially understood factors: stress hormones, oxidation pathways and metabolic pathways. Epigenetic programming — the heritable, on-the-fly form of gene regulation that allows for rapid adaptation to circumstance — is also important.

The latest findings reinforce the researchers’ suspicion that telomere biology plays a role, too. In earlier studies of the same group, telomere length tracked with immune system problems and metabolic dysregulation.

The 94 people in this group are all young adults, carefully selected for demographic comparability. When their telomeres were read for this latest study, they were 25 years old. The extra 3.5 years of white blood cell aging in prenatally stressed people hides a gender difference: In women, prenatally stressed telomeres were shorter by the equivalent of about 5 years’ wear and tear.

Whether short telomeres cause the problems or just reflect them remains to be determined, but a basic pattern is clear: Stress in the womb can set up “a long-term trajectory at birth,” write the researchers.

Note: Several of the paper’s authors are co-founders of Telome Health, a company that offers health-related telomere testing (though not longevity-related testing).

Top image: Menno Hordijk/Flickr.

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Citation: “Stress exposure in intrauterine life is associated with shorter telomere length in young adulthood.” By Sonja Entringer, Elissa S. Epel, Robert Kumsta, Jue Lin, Dirk H. Hellhammer, Elizabeth H. Blackburn, Stefan Wu?st, and Pathik D. Wadhwa