title: The effect of preimplantation genetic screening on neurological, cognitive and behavioural development in 4-year-old children: follow-up of a RCT.
abstract: OBJECTIVE
  Does embryo biopsy inherent to preimplantation genetic screening (PGS) affect neurological, cognitive and behavioural development of 4-year-old children?
  
  
  CONCLUSIONS
  PGS does not seem to affect neurological, cognitive and behavioural development of 4-year-old singletons; however, our data suggest that it may be associated with altered neurodevelopment in twins.
  
  
  BACKGROUND
  Evidence concerning the safety of PGS on neurodevelopmental outcome in offspring is scarce. The present study provides information on neurodevelopmental, cognitive and behavioural outcome of 4-year-old PGS offspring.
  
  
  METHODS
  A prospective, assessor-blinded follow-up study of children born to women who participated in a multi-centre RCT on the effect of IVF with or without PGS.
  
  
  METHODS
  At 4 years, 49 children (31 singletons, 9 sets of twins) born following IVF with PGS and 64 children (42 singletons, 11 sets of twins) born following IVF without PGS (controls) were assessed (post-natal attrition 18%). Neurological development was evaluated with the standardized, age-specific and sensitive neurological examination according to Hempel, resulting in a neurological optimality score (NOS), a fluency score and the rate of adverse neurological outcome. Primary outcome was the fluency score, as fluency of movements is easily reduced by subtle dysfunction of the brain. Cognitive development was evaluated with the Kaufman Assessment Battery for Children; behavioural development was evaluated with the Child Behavior Checklist. The effect of PGS was analysed with a mixed effects model.
  
  
  RESULTS
  Based on the intention to treat analysis, neurodevelopmental outcome of PGS children was similar to that of controls. However, additional analyses indicated that PGS affected neurodevelopmental outcome of twins in a different way than that of singletons. The fluency score of singletons born following PGS was similar to that of control singletons [mean values, 95% confidence intervals (CIs): 12.2 (11.5;12.8) and 12.2 (11.6;12.8)], respectively, P = 0.977) that was also true for the other neurodevelopmental parameters. The fluency score of PGS twins was significantly lower than that of control twins [mean values, 95% CIs: 10.6 (9.8;11.3) and 12.3 (11.5;13.1)], respectively, P = 0.001); the same was true for the NOS. In addition, PGS in twins was associated with a higher sequential intelligence quotient score. On the other hand, other neurodevelopmental parameters were similar for PGS twins and control twins. Post hoc sample size calculation for the primary outcome parameter, the fluency score, indicated that the study groups, including the subgroups of singletons and twins, were adequately powered.
  
  
  CONCLUSIONS
  We assessed singletons and twins who contributed to the generalizability of the study. A limitation of our study is the relative small size of our study groups and the selective dropout in both groups (dropouts PGS group: higher gestational age; control group: less well-educated parents). These preclude the conclusion that PGS per se is not associated with neurodevelopmental, cognitive and behavioural problems in singletons and the conclusion that PGS is associated with altered neurodevelopmental outcome in twins.
  
  
  CONCLUSIONS
  The need for careful long-term monitoring of children born following embryo biopsy remains, as it is still applied in the form of PGD and it is still unknown whether embryo biopsy affects long-term neurodevelopmental outcome.
authors.affiliation: Department of Paediatrics, Division of Developmental Neurology-CA 85, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands.
authors.forename: P
authors.initials: P
authors.lastname: Schendelaar
authors.forename: K J
authors.initials: KJ
authors.lastname: Middelburg
authors.forename: A F
authors.initials: AF
authors.lastname: Bos
authors.forename: M J
authors.initials: MJ
authors.lastname: Heineman
authors.forename: J H
authors.initials: JH
authors.lastname: Kok
authors.forename: S
authors.initials: S
authors.lastname: La Bastide-Van Gemert
authors.forename: J
authors.initials: J
authors.lastname: Seggers
authors.forename: E R
authors.initials: ER
authors.lastname: Van den Heuvel
authors.forename: M
authors.initials: M
authors.lastname: Hadders-Algra
mesh_terms: D002657:Child Development; D002675:Child, Preschool; D005307:Fertilization in Vitro / Q000009:adverse effects; D005500:Follow-Up Studies; D006801:Humans; D009460:Neurologic Examination; D019836:Preimplantation Diagnosis / Q000009:adverse effects*; D016032:Randomized Controlled Trials as Topic; D014427:Twins
keywords: IVF; children; follow-up; neurodevelopmental outcome; preimplantation genetic screening