title: A comparison of perinatal outcomes in singletons and multiples born after in vitro fertilization or intracytoplasmic sperm injection stratified for neonatal risk criteria.
abstract: OBJECTIVE
  To compare perinatal singleton and multiple outcomes in a large Dutch in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) population and within risk subgroups. Newborns were assigned to a risk category based on gestational age, birthweight, Apgar score and congenital malformation.
  
  
  METHODS
  Register-based retrospective cohort study.
  
  
  METHODS
  Netherlands Perinatal Registry data.
  
  
  METHODS
  A total of 3041 singletons and 1788 multiple children born from IVF/ICSI in 2003-2005.
  
  
  METHODS
  Student's t-test or Mann-Whitney U-test was used to analyze continuous data, chi-squared analyses were used for categorical data. Multivariate logistic and linear regression analysis was performed to analyze whether the risk stratification criteria were associated with neonatal hospital admission and length of stay.
  
  
  METHODS
  Start of labor, mode of delivery, gestational age, birthweight, 5-min Apgar score, congenital malformation, neonatal hospital admission, neonatal intensive care unit admission and mortality.
  
  
  RESULTS
  IVF/ICSI-conceived multiples had considerably poorer outcomes than singletons in terms of cesarean section rate, preterm birth, birthweight, being small-for-gestational-age, Apgar score, neonatal hospital admission, neonatal intensive care unit admission and neonatal mortality. As opposed to the results found in the total study population and the low-risk and moderate-risk populations, high-risk multiples showed better outcomes than high-risk singletons regarding cesarean section rate, birthweight and Apgar score. All risk stratification variables were associated with being hospitalized after birth. Length of stay was associated with all risk stratification criteria except Apgar score.
  
  
  CONCLUSIONS
  Perinatal outcomes in IVF/ICSI-conceived multiples are considerably poorer than in singletons. This finding mainly pertains to low-risk children. High-risk multiples had significantly better perinatal outcomes than high-risk singletons.
authors.affiliation: Department of Clinical Epidemiology and Medical Technology Assessment, Maastricht University Medical Center, Maastricht, the Netherlands.
authors.forename: Mirjam M J
authors.initials: MM
authors.lastname: van Heesch
authors.forename: Johannes L H
authors.initials: JL
authors.lastname: Evers
authors.forename: John C M
authors.initials: JC
authors.lastname: Dumoulin
authors.forename: Mark A H B M
authors.initials: MA
authors.lastname: van der Hoeven
authors.forename: Catharina E M
authors.initials: CE
authors.lastname: van Beijsterveldt
authors.forename: Gouke J
authors.initials: GJ
authors.lastname: Bonsel
authors.forename: Ramon H M
authors.initials: RH
authors.lastname: Dykgraaf
authors.forename: Johannes B
authors.initials: JB
authors.lastname: van Goudoever
authors.forename: Corine
authors.initials: C
authors.lastname: Koopman-Esseboom
authors.forename: Willianne L D M
authors.initials: WL
authors.lastname: Nelen
authors.forename: Katerina
authors.initials: K
authors.lastname: Steiner
authors.forename: Pieter
authors.initials: P
authors.lastname: Tamminga
authors.forename: Nino
authors.initials: N
authors.lastname: Tonch
authors.forename: Piet
authors.initials: P
authors.lastname: van Zonneveld
authors.forename: Carmen D
authors.initials: CD
authors.lastname: Dirksen
mesh_terms: D000328:Adult; D001034:Apgar Score; D001724:Birth Weight; D015331:Cohort Studies; D000013:Congenital Abnormalities / Q000453:epidemiology; D005260:Female; D005307:Fertilization in Vitro; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007363:Intensive Care Units, Neonatal / Q000706:statistics & numerical data; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D009099:Multiple Birth Offspring / Q000706:statistics & numerical data*; D009426:Netherlands; D011247:Pregnancy; D011256:Pregnancy Outcome; D011272:Pregnancy, Multiple / Q000502:physiology* / Q000706:statistics & numerical data; D012042:Registries; D012044:Regression Analysis; D012189:Retrospective Studies; D012307:Risk Factors; D012923:Social Class; D020554:Sperm Injections, Intracytoplasmic
keywords: In vitro fertilization; intracytoplasmic sperm injection; multiple pregnancy; multiples; perinatal outcome; singletons