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Pregnancy Timeline by SemestersDevelopmental TimelineFertilizationFirst TrimesterSecond TrimesterThird TrimesterFirst Thin Layer of Skin AppearsEnd of Embryonic PeriodEnd of Embryonic PeriodFemale Reproductive SystemBeginning Cerebral HemispheresA Four Chambered HeartFirst Detectable Brain WavesThe Appearance of SomitesBasic Brain Structure in PlaceHeartbeat can be detectedHeartbeat can be detectedFinger and toe prints appearFinger and toe prints appearFetal sexual organs visibleBrown fat surrounds lymphatic systemBone marrow starts making blood cellsBone marrow starts making blood cellsInner Ear Bones HardenSensory brain waves begin to activateSensory brain waves begin to activateFetal liver is producing blood cellsBrain convolutions beginBrain convolutions beginImmune system beginningWhite fat begins to be madeHead may position into pelvisWhite fat begins to be madePeriod of rapid brain growthFull TermHead may position into pelvisImmune system beginningLungs begin to produce surfactant
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Mom's BMI may affect biological age of her baby

Higher Body Mass Index (BMI) in a mother before pregnancy is associated with shorter telomere length — a biomarker for biological age — in her newborn. Her baby's short telomere length means the baby's cells have shorter lifespans.

A study published in the open access journal BMC Medicine involving 743 mothers and their babies, was conducted by researchers at Hasselt University, Belgium. Their work is the first to report a strong association between a mothers' BMI and the telomere lengths in her newborn.

Telomeres are structures at the ends of chromosomes which are vital in maintaining the stability of a person's genome. They protect chromosomes from degrading, and have been compared to the plastic tips protecting the ends of shoelaces. Telomere length is measured by their number of DNA base pairs (guanine-cytosine and adenine-thymine). This number is directly linked to the number of times a cell can divide in its lifetime. Longer telomeres allow cells to divide more often, linking telomere length with biological age.

Telomere length in adults is also seen to be associated with age-related diseases — such as cardiovascular disease, type 2 diabetes and an increase in mortality. But telomere research on newborns has been limited.

To examine the association between maternal BMI and newborn telomere length, researchers examined 743 mothers, between 17 and 44 years of age, and their newborn babies. Through questionnaires, detailed information on maternal and paternal age, socioeconomic status, smoking status, parity, ethnicity and pregnancy complications was collected. Umbilical cord blood was drawn immediately after delivery from all 743 mother-newborn pairs to measure average telomere lengths.

"Compared with newborns of mothers with a normal BMI, newborns of women with obesity are older on a molecular level, as shortened telomere lengths mean their cells have shorter lifespans.

"So maintaining a healthy BMI during a woman's reproductive age may promote molecular longevity in her offspring."

Tim Nawrot PhD, professor in epidemiology, risk assessment, and genetic susceptibility, Hasselt University, Belgium; advisor on national and international panels in the field of environmental health, World Health Organisation and Canadian Health Administration; honored by the Belgian Academies of Medicine for work on environmental epidemiology; and corresponding author.

Previous studies have shown that people normally lose about 32.2 to 45.5 telomere base pairs per year as adults. Researchers found that for each one-point increase in a mothers' BMI, telomeres in her baby were about 50 base pairs shorter. The loss of 50 base pairs is equivalent to what people normally lose in 1.1 to 1.6 years as adults — and may indicate an increase in their risk for chronic diseases as adults.

Dries Martens, co-author of the paper: "We ruled out many other potential factors that may be associated with telomere length, including parents' age at birth, socio-economic class, ethnicity, maternal smoking status, newborns' gender or birth weight."

"Prior to our study, there was no evidence of any association between pre-pregnancy BMI and newborn telomere length — although meta-analyses suggest an association between BMI and telomere length in adults. 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."

Tim Nawrot PhD

The researchers are aware their study is limited by lack of paternal BMI information. Previous research has described epigenetic effects of paternal weight on newborns.

Abstract Background
Newborn telomere length sets telomere length for later life. At birth, telomere length is highly variable among newborns and the environmental factors during in utero life for this observation remain largely unidentified. Obesity during pregnancy might reflect an adverse nutritional status affecting pregnancy and offspring outcomes, but the association of maternal pre-pregnancy body mass index (BMI) with newborn telomere length, as a mechanism of maternal obesity, on the next generation has not been addressed .Results Maternal age was 29.1 years (range, 1744) and mean (SD) pre-pregnancy BMI was 24.1 (4.1) kg/m2. Decline in newborn telomere length occurred in parallel with higher maternal pre-pregnancy BMI. Independent of maternal and paternal age at birth, maternal education, gestational age, newborn gender, ethnicity, birthweight, maternal smoking status, parity, cesarean section, and pregnancy complications, each kg/m2 increase in pre-pregnancy BMI was associated with a -0.50 % (95 % CI, -0.83 to -0.17 %; P = 0.003) shorter cord blood telomere length and a -0.66 % (95 % CI, -1.06 to -0.25 %; P = 0.002) shorter placental telomere length. Conclusions Maternal pre-pregnancy BMI is associated with shorter newborn telomere lengths as reflected by cord blood and placental telomeres. These findings support the benefits of a pre-pregnancy healthy weight for promoting molecular longevity from early life onwards.

Design We examined both gene expression and gene regulation (chromatin accessibility) in non-inflamed colon tissue from a cohort of adult patients with CD and control patients. To support the generality of our findings, we analysed previously published expression data from a large cohort of treatment-naïve paediatric CD and control ileum.

Keywords: Telomeres Newborns Pre-pregnancy body-mass index in utero life.

BMC Medicine is an open access, open peer-reviewed general medical journal publishing outstanding and influential research in all areas of clinical practice, translational medicine, public health, policy, and general topics of interest to the biomedical research community. As the flagship medical journal of the BMC series, we also publish stimulating debates and reviews as well as unique forum articles and concise tutorials. BioMed Central is an STM (Science, Technology and Medicine) publisher which has pioneered the open access publishing model. All peer-reviewed research articles published by BioMed Central are made immediately and freely accessible online, and are licensed to allow redistribution and reuse. BioMed Central is part of Springer Nature, a major new force in scientific, scholarly, professional and educational publishing, created in May 2015 through the combination of Nature Publishing Group, Palgrave Macmillan, Macmillan Education and Springer Science+Business Media. http://www.biomedcentral.com.

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PURPLE chromosomes. RED telomeres.
Image Credit: NASA


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