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Pre-pregnancy BMI correlated with newborn telomere length

The higher a pre-pregnant woman’s BMI, the more likely her baby will have shorter telomere length, according to research published in BMC Medicine.

"Prior to our study, there was no evidence of an association between pre-pregnancy BMI and newborn telomere length, although meta-analyses suggest an association between BMI and telomere length in adults,” Tim S. Nawrot, PhD, department of public health and primary care, Leuven University, Belgium, said in a press release. “Our results add to the growing body of evidence that high maternal BMI impacts fetal programming, which could lead to altered fetal development and later life diseases. The public health impact of our findings is considerable as in affluent societies about 30% of women of reproductive age are overweight."

Nawrot and colleagues measured the average telomere lengths in cord blood in babies of 743 mother-newborn pairs. They also measured average telomere lengths in placental tissue of 702 babies. The mean BMI of the mothers was 24.1 kg/m². Researchers also compiled data on type of birth, baby’s sex and ethnicity, mother’s age at pregnancy, education level, medical history and smoking habits, as well as the baby’s parents’ ages when the baby was born.

“The fact that telomere length at birth is very variable among newborns is intriguing as it suggests that newborns have a wide biological age range. This initial telomere length is partially heritable but environmental factors might influence initial telomere length even before birth,” Nawrot told Healio Family Medicine. “Identifying factors that contribute to the setting of telomere length at birth is important as by altering these factors, this may increase life expectation and reduce later life comorbidities in future generations.”

Researchers found each kg/m² increase in pre-pregnancy BMI translated to a −0.5% (95 % CI, −0.83 to −0.17) shorter cord blood telomere length; the relative telomere length ranged from 0.51 to 1.75. Researchers observed a −0.66% (95% CI, −1.06 to −0.25) shorter placental telomere length; the relative telomere length ranged from 0.52 to 1.89. Researchers noted these associations remained unchanged after adjustments for age at pregnancy, birth weight, baby’s sex, mother’s education and mother and father’s age at birth were taken into consideration.

“We think that doctors should mention potential risks of being overweight and that this might have consequences during pregnancy and may have consequences for their newborn,” Nawrot said. “ … [A]ccording to this research, [having the discussion] even before pregnancy is important.”– by Janel Miller

Disclosure: The researchers report no relevant financial disclosures.