HealthDay News — Prenatal exposure to tobacco is associated with shorter fetal telomere length, according to research in the American Journal of Obstetrics & Gynecology.

To determine whether maternal smoking during pregnancy affects telomere length of the fetus, Hamisu M. Salihu, MD, PhD, of the University of South Florida in Tampa, and colleagues administered self-reported questionnaires and salivary cotinine tests to conform tobacco exposure in pregnant female patients.

Genomic DNA from neonatal umbilical cord blood was analyzed to assess fetal telomere length. The ratio of relative telomere length was determined by the ratio of telomere repeat copy number to single copy gene copy number (T/S ratio).

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Smoking was inversely related to fetal telomere length in a dose-response pattern, found the investigators. T/S ratio was greater in descending order in nonsmokers, compared with passive smokers, than in active smokers. For each pairwise comparison, significant differences were observed in telomere length. The greatest difference in telomere length was found between active smokers and nonsmokers.

“Our findings suggest the possibility of early intrauterine programming for accelerated aging that is the result of tobacco exposure,” concluded the researchers.


  1. Salihu HM et al. American Journal of Obstetrics & Gynecology. 2015; doi: