title: 'Vanishing embryo syndrome' in IVF/ICSI.
abstract: BACKGROUND
  In a Danish population-based cohort study assessing the risk of cerebral palsy in children born after IVF, we made some interesting observations regarding 'vanishing co-embryos'.
  
  
  RESULTS
  All live-born children born in Denmark from 1 January 1995 to 31 December 2000 were included in this analysis. The children conceived by IVF/ICSI (9444) were identified through the IVF Register, the children conceived without IVF/ICSI (395 025) were identified through The Danish Medical Birth Register. Main outcome measure was the incidence of cerebral palsy. Within the IVF/ICSI children we found indications of an increased risk of cerebral palsy in those children resulting from pregnancies, where the number of embryos transferred was higher than the number of children born.
  
  
  CONCLUSIONS
  The association between vanishing embryo syndrome and incidence of cerebral palsy following IVF requires further investigation in larger, adequately powered, studies.
authors.affiliation: NANEA, Department of Epidemiology, Institute of Public Health, University of Aarhus, 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
authors.initials: D
authors.lastname: Schendel
authors.forename: Michael
authors.initials: M
authors.lastname: Vaeth
authors.forename: Erik
authors.initials: E
authors.lastname: Ernst
authors.forename: Lene
authors.initials: L
authors.lastname: Nielsen
authors.forename: Poul
authors.initials: P
authors.lastname: Thorsen
mesh_terms: D002547:Cerebral Palsy / Q000453:epidemiology; D020964:Embryo Loss / Q000453:epidemiology*; D005260:Female; D005307:Fertilization in Vitro / Q000706:statistics & numerical data*; D006801:Humans; D015994:Incidence; D011247:Pregnancy; D011272:Pregnancy, Multiple / Q000706:statistics & numerical data*; D012042:Registries / Q000706:statistics & numerical data; D012307:Risk Factors; D020554:Sperm Injections, Intracytoplasmic / Q000706:statistics & numerical data*