title: Does confined placental mosaicism account for adverse perinatal outcomes in IVF pregnancies?
abstract: BACKGROUND
  IVF singletons have poorer perinatal outcomes than singletons from spontaneous conceptions. This may be due to the influence of ovarian stimulation on the chromosomal constitution of the embryos which could be translated into localized chromosomal anomalies in the placenta. The aim of this study was to compare the incidence of confined placental mosaicism (CPM) in IVF/ICSI pregnancies and spontaneous conceptions.
  
  
  METHODS
  We conducted a multi-centre retrospective analysis of karyotype results obtained by chorionic villus sampling (CVS), performed due to advanced maternal age (>or=36 years at 18 weeks of gestation), in the Netherlands between 1995 and 2005.
  
  
  RESULTS
  From a total of 322 246 pregnancies, 20 885 CVS results were analysed: 235 in the IVF/ICSI group and 20 650 in the control group. The mean age of women in both groups was 38.4 years (mean difference -0.08, 95% CI -0.35 to 0.18). Data relating to the fetal karyotype were missing in 143 cases in the control group. When taking into account missing data, the incidence of CPM was lower in the IVF-ICSI group than in the control group, 1.3% versus 2.2% (odds ratio 0.59, 95% CI 0.19-1.85), whereas the incidence of fetal chromosomal anomalies was increased 4.3% versus 2.4% (odds ratio 1.81, 95% CI 0.95-3.42). Neither differences were statistically significant.
  
  
  CONCLUSIONS
  The incidence of CPM is not increased in IVF/ICSI pregnancies compared with spontaneous conceptions. CPM probably does not account for the adverse perinatal outcomes following IVF/ICSI.
authors.affiliation: Department of Reproductive Medicine and Gynaecology, University Medical Centre, Utrecht, The Netherlands. b.c.jacod@students.uu.nl
authors.forename: B C
authors.initials: BC
authors.lastname: Jacod
authors.forename: K D
authors.initials: KD
authors.lastname: Lichtenbelt
authors.forename: G H
authors.initials: GH
authors.lastname: Schuring-Blom
authors.forename: J S E
authors.initials: JS
authors.lastname: Laven
authors.forename: D
authors.initials: D
authors.lastname: van Opstal
authors.forename: M J C
authors.initials: MJ
authors.lastname: Eijkemans
authors.forename: N S
authors.initials: NS
authors.lastname: Macklon
mesh_terms: D000328:Adult; D015193:Chorionic Villi Sampling; D005260:Female; D005307:Fertilization in Vitro; D005333:Fetus / Q000166:cytology; D006801:Humans; D007621:Karyotyping; D009030:Mosaicism; D010062:Ovulation Induction / Q000009:adverse effects; D010920:Placenta / Q000166:cytology*; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000235:genetics*; D012189:Retrospective Studies; D020554:Sperm Injections, Intracytoplasmic