title: Obstetric and neonatal risks among extremely macrosomic babies and their mothers.
abstract: OBJECTIVE
  We estimated the risk of complications at birth of extremely large babies (≥5000 g).
  
  
  METHODS
  This was a cohort study including all births of extremely large babies in 1996 through 2005 and comparison cohort with normal birthweight (1:2) identified in the national birth registration.
  
  
  RESULTS
  There were 343 extremely large babies or 0.9% of all singletons. Compared to the normal birthweight cohort (n = 679), there were increased odds of shoulder dystocia (odds ratio [OR], 26.9; 95% confidence interval [CI], 11.1-65.1), emergency cesarean section (OR, 5.2; 95% CI, 3.4-8.0), and failed labor induction (OR, 4.3; 95% CI, 1.7-11.0). The risk of elective section was not increased (OR, 1.1; 95% CI, 0.6-2.0). Minor congenital malformations were more frequent (OR, 2.1; 95% CI, 1.2-3.7), as were birth injuries (OR, 3.7; 95% CI, 2.1-6.8) and minor metabolic disturbance (OR, 2.5; 95% CI, 1.1-6.2), but not asphyxial births.
  
  
  CONCLUSIONS
  The risk of shoulder dystocia for very large babies is markedly raised, as are minor complications, while for mothers the main risk is emergency section.
authors.affiliation: Faculty of Medicine, University of Iceland, Reykjavík, Iceland.
authors.forename: Harpa
authors.initials: H
authors.lastname: Vidarsdottir
authors.forename: Reynir Tomas
authors.initials: RT
authors.lastname: Geirsson
authors.forename: Hildur
authors.initials: H
authors.lastname: Hardardottir
authors.forename: Unnur
authors.initials: U
authors.lastname: Valdimarsdottir
authors.forename: Atli
authors.initials: A
authors.lastname: Dagbjartsson
mesh_terms: D000328:Adult; D001720:Birth Injuries / Q000209:etiology*; D001724:Birth Weight; D002585:Cesarean Section; D004420:Dystocia / Q000209:etiology*; D005260:Female; D005320:Fetal Macrosomia / Q000150:complications*; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy; D012042:Registries; D012189:Retrospective Studies; D012306:Risk; D012307:Risk Factors