Prepregnancy Maternal BMI May Affect Infant Telomere Length

Jennifer Garcia

October 18, 2016

High maternal prepregnancy body mass index (BMI) may result in shorter telomere length and affect the biological age of the newborn, according to results of a study published online October 18 in BMC Medicine.

Dries S. Martens, PhD, from the Centre for Environmental Sciences, Hasselt University in Belgium, and colleagues measured telomere length in umbilical cord blood (743 mother–newborn pairs) and placental tissue (702 mother–newborn pairs) between February 1, 2010, and February 1, 2015. Cord blood and placental DNA were collected within 10 minutes of delivery.

The researchers found that for every kilogram per square meter increase in prepregnancy BMI, cord blood telomere length was 0.50% shorter (95% confidence interval, −0.83% to −0.17%; P = .003), and placental telomere length was 0.66% shorter (95% confidence interval, −1.06% to −0.25%; P = .002).

"The telomere loss in newborns of obese mothers may increase the risk for chronic diseases in adulthood," the study authors write.

This association was independent of parental age at birth, maternal education, smoking status, parity, and pregnancy complications, as well as newborn sex, ethnicity, or birthweight. Mothers with higher prepregnancy BMI also experienced more pregnancy complications, were more likely to undergo cesarean delivery, and had higher newborn birth weights. There was no observed association between weight gain during pregnancy and telomere length.

The researchers collected prepregnancy weight and weight at the time of delivery from the medical records. The average maternal age was 29.1 years, and the mean prepregnancy BMI was 24.1 kg/m2 (standard deviation, 4.1 kg/m2). The researchers defined prepregnancy BMI categories as follows: normal, less than 25 kg/m2; overweight, from 25 kg/m2 to less than 30 kg/m2; and obese, 30 kg/m2 or more. Prepregnancy BMI for all mothers was less than 40 kg/m2.

The researchers note that a 0.50% decrease in telomere length for every maternal BMI unit increase could result in "a loss of 1.1 to 1.6 telomeric year equivalence in adulthood."

"This illustrates the public health significance of our findings, as newborns from obese mothers compared with newborns from normal weight mothers were biologically approximately 12 to 17 years older, based on telomeric year equivalence in adulthood," write the authors.

The researchers acknowledge limitations of the study, such as the lack of information regarding paternal BMI and its possible effects on fetal development, as well as the variability of polymerase chain assay to determine telomere length.

The authors emphasize, however, that their "findings shed light on the pre-pregnancy effects of maternal BMI on the next generation" and "add to the growing body of evidence that high maternal BMI impacts fetal programming."

Funding for the study was provided by the European Research Council and the Flemish Scientific Fund. The authors have disclosed no relevant financial relationships.

BMC Med. Published online October 18, 2016. Full text

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