title: Discordant twin growth in utero and differences in blood pressure and endothelial function at 8 years of age.
abstract: OBJECTIVE
  Low birth weight is associated with increased prevalence of hypertension and cardiovascular disease in adults. The aim of this study was to evaluate genetic and intrauterine environmental contributions to blood pressure (BP) and vascular functions in twins with discordant growth in utero.
  
  
  METHODS
  We studied 31 twin pairs (21 monozygous and nine dizygous), mean age 8 years) with large within-pair differences in birth weight. Among the monozygous pairs, nine had suffered from twin-to-twin-transfusion syndrome (TTTS).
  
  
  METHODS
  Apart from BP, we determined diameters and elasticity of the carotid artery and abdominal aorta with ultrasonography, and endothelial function in skin vessels with a laser Doppler technique, before and after transdermal delivery of acetylcholine and nitroglycerin.
  
  
  RESULTS
  Eight of 62 twin subjects had a systolic BP above the 90th percentile in a North-American reference population. Among these, seven/eight were monozygous with a history of poor fetal growth and/or TTTS. In monozygous twin pairs without TTTS, systolic BP and pulse pressure were higher and vascular endothelial function was impaired in the lower birth weight twin. In the TTTS group, the lighter twin had a narrower carotid artery but there was no within-pair difference in arterial elasticity. Pre-eclampsia during the index pregnancy enhanced within-pair differences in BP but abolished within-pair differences in endothelial function.
  
  
  CONCLUSIONS
  Severe fetal growth retardation contributes to higher BP, arterial narrowing and endothelial dysfunction in childhood. Pre-eclampsia may act both as an effect modifier and confounder of these associations.
authors.affiliation: Department of Pediatrics, Stockholm Soeder Hospital, Karolinska Institutet, Stockholm, Sweden. cecilia.halvorsen@sodersjukhuset.se
authors.forename: C P
authors.initials: CP
authors.lastname: Halvorsen
authors.forename: E
authors.initials: E
authors.lastname: Andolf
authors.forename: J
authors.initials: J
authors.lastname: Hu
authors.forename: C
authors.initials: C
authors.lastname: Pilo
authors.forename: B
authors.initials: B
authors.lastname: Winbladh
authors.forename: M
authors.initials: M
authors.lastname: Norman
mesh_terms: D000109:Acetylcholine; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging; D001794:Blood Pressure; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000187:drug effects / Q000503:physiopathology*; D002339:Carotid Arteries / Q000000981:diagnostic imaging; D002648:Child; D004200:Diseases in Twins / Q000503:physiopathology*; D004730:Endothelium, Vascular / Q000000981:diagnostic imaging / Q000187:drug effects / Q000503:physiopathology*; D005260:Female; D047109:Fetal Development; D005317:Fetal Growth Retardation / Q000503:physiopathology*; D005500:Follow-Up Studies; D006801:Humans; D017078:Laser-Doppler Flowmetry; D008297:Male; D005996:Nitroglycerin; D012867:Skin / Q000098:blood supply; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic; D014463:Ultrasonography; D014665:Vasodilator Agents
chemical_list: D014665:Vasodilator Agents; D005996:Nitroglycerin; D000109:Acetylcholine