Women who have given birth have shorter telomeres – the end caps of DNA on chromosomes – compared with those who have not had a child, a study conducted by researchers at the Department of Global and Community Health at George Mason University in Virginia suggests. Telomeres, which shorten naturally with age, help DNA replicate. Telomere length is associated with disease risk (morbidity) and mortality.
For this study, researchers used information from the National Health and Nutrition Examination Survey, which is representative of the U.S. population. They found that telomere length in women who had given birth was the equivalent of about 11 years shorter than in women who had not had children. This variation is larger than what was observed in studies examining the effects of obesity and smoking on telomere length.
The researchers were unable to determine whether childbirth shortens telomeres or if telomeres are shorter to begin with in women who’ve had a child. Results of the study were published in Human Reproduction.