title: Placental telomere length decreases with gestational age and is influenced by parity: a study of third trimester live-born twins.
abstract: BACKGROUND
  In contrast to the postnatal period, little is known about telomere length (TL) during prenatal life. The decrease in placental TL remains unknown, although intra uterine growth retardation and preeclampsia are associated with shorter placental TL. The aim of this study is to assess the decrease of placental TL during the third trimester of gestation and to explore the role of potential "growth influencing factors".
  
  
  METHODS
  The study sample consisted of 329 live-born twins from the East Flanders Prospective Twin Survey. TL was determined using a multiplex quantitative PCR method. Gestational age, sex, birth order, placental characteristics, parity, maternal and paternal age, diabetes, hypertension, smoking, alcohol use, and socio economic status (SES) were considered "growth influencing factors". Bivariable multilevel regression analysis with "growth influencing factors" was performed.
  
  
  RESULTS
  Placental TL ranged from 4.3 kbp to 84.4 kbp with a median of 10.8 kbp. Ln(TL) decreased in a linear fashion with an estimated TL decreasing from 13.98 kbp at 28 weeks to 10.56 kbp at 42 weeks. The regression coefficient of gestational age became smaller if considered together with SES (b = -0.017; p = 0.08) or diabetes (b = -0.018; p = 0.07) and bigger if considered together with parity (b = -0.022; p = 0.02), indicating that part of the association between gestational age and telomere length is explained by these three confounding factors.
  
  
  CONCLUSIONS
  Placental TL decreases during the third trimester of gestation of live-born twins with approximately 25% indicating that telomere shortening may play a role in aging of the placenta.
authors.affiliation: NUTRIM School for Nutrition, Toxicology and Metabolism, The Netherlands; Department of Complex Genetics, Cluster of Genetics and Cell Biology, The Netherlands; Centre of Human Genetics, University Hospitals Leuven & Department of Human Genetics, KU, Leuven, Belgium. Electronic address: marij.gielen@maastrichtuniversity.nl.
authors.forename: M
authors.initials: M
authors.lastname: Gielen
authors.affiliation: NUTRIM School for Nutrition, Toxicology and Metabolism, The Netherlands; Department of Toxicology, The Netherlands.
authors.forename: G
authors.initials: G
authors.lastname: Hageman
authors.affiliation: NUTRIM School for Nutrition, Toxicology and Metabolism, The Netherlands; Department of Toxicology, The Netherlands.
authors.forename: D
authors.initials: D
authors.lastname: Pachen
authors.affiliation: Centre of Human Genetics, University Hospitals Leuven & Department of Human Genetics, KU, Leuven, Belgium.
authors.forename: C
authors.initials: C
authors.lastname: Derom
authors.affiliation: Centre of Human Genetics, University Hospitals Leuven & Department of Human Genetics, KU, Leuven, Belgium.
authors.forename: R
authors.initials: R
authors.lastname: Vlietinck
authors.affiliation: NUTRIM School for Nutrition, Toxicology and Metabolism, The Netherlands; Department of Complex Genetics, Cluster of Genetics and Cell Biology, The Netherlands.
authors.forename: M P
authors.initials: MP
authors.lastname: Zeegers
mesh_terms: D005260:Female; D005865:Gestational Age; D006801:Humans; D008297:Male; D010298:Parity / Q000502:physiology*; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D011446:Prospective Studies; D016615:Telomere / Q000378:metabolism*; D059506:Telomere Shortening / Q000502:physiology*; D014427:Twins
keywords: Growth; Prenatal; Telomere attrition; Telomere length; Twins