title: Cerebral palsy among children born after in vitro fertilization: the role of preterm delivery--a population-based, cohort study.
abstract: OBJECTIVE
  Our aim was to assess the incidence of cerebral palsy among children conceived with in vitro fertilization and children conceived without in vitro fertilization.
  
  
  METHODS
  A population-based, cohort study, including all live-born singletons and twins born in Denmark between January 1, 1995, and December 31, 2000, was performed. Children conceived with in vitro fertilization (9255 children) were identified through the In Vitro Fertilization Register; children conceived without in vitro fertilization (394,713) were identified through the Danish Medical Birth Register. Cerebral palsy diagnoses were obtained from the National Register of Hospital Discharges. The main outcome measure was the incidence of cerebral palsy in the in vitro fertilization and non-in vitro fertilization groups.
  
  
  RESULTS
  Children born after in vitro fertilization had an increased risk of cerebral palsy; these results were largely unchanged after adjustment for maternal age, gender, parity, small-for-gestational age status, and educational level. The independent effect of in vitro fertilization vanished after additional adjustment for multiplicity or preterm delivery. When both multiplicity and preterm delivery were included in the multivariate models, preterm delivery remained associated strongly with the risk of cerebral palsy.
  
  
  CONCLUSIONS
  The large proportions of preterm deliveries with in vitro fertilization, primarily for twins but also for singletons, pose an increased risk of cerebral palsy.
authors.affiliation: North Atlantic Neuro-Epidemiology Alliances, Department of Epidemiology, University of Aarhus, Paludan-Müllers vej 17, 8000 Aarhus C, Denmark. dh@soci.au.dk
authors.forename: Dorte
authors.initials: D
authors.lastname: Hvidtjørn
authors.forename: Jakob
authors.initials: J
authors.lastname: Grove
authors.forename: Diana E
authors.initials: DE
authors.lastname: Schendel
authors.forename: Michael
authors.initials: M
authors.lastname: Vaeth
authors.forename: Erik
authors.initials: E
authors.lastname: Ernst
authors.forename: Lene F
authors.initials: LF
authors.lastname: Nielsen
authors.forename: Poul
authors.initials: P
authors.lastname: Thorsen
mesh_terms: D000328:Adult; D001925:Brain Damage, Chronic / Q000453:epidemiology / Q000209:etiology; D002547:Cerebral Palsy / Q000453:epidemiology* / Q000209:etiology; D015331:Cohort Studies; D003718:Denmark / Q000453:epidemiology; D004200:Diseases in Twins / Q000453:epidemiology / Q000209:etiology; D004522:Educational Status; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000453:epidemiology* / Q000209:etiology; D007236:Infant, Small for Gestational Age; D008297:Male; D008423:Maternal Age; D007752:Obstetric Labor, Premature / Q000453:epidemiology*; D010298:Parity; D011247:Pregnancy; D011272:Pregnancy, Multiple; D016016:Proportional Hazards Models; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors; D020554:Sperm Injections, Intracytoplasmic / Q000706:statistics & numerical data