Reduced movement variation in infants born following IVF with ovarian hyperstimulation

Introduction: The effect of in vitro fertilization (IVF) on neurodevelopmental outcome is unclear. Probably, IVF does not affect traditional measures of neurological development in infancy, but little is known on long-term effects. Recently a new video-based instrument to evaluate neuromotor development was developed. The Infant Motor Profile (IMP) evaluates neuromotor condition in infants in terms of the quality of spontaneous motor behaviour. The IMP does not only assess traditional neuromotor domains, such as performance, symmetry and movement fluency, but also two novel domains: variation and variability. Movement variation denotes the size of the child's movement repertoire. Previous studies demonstrated that reduced movement variation is associated with early lesions of the periventricular white matter and - more generally - reflects the integrety of cortical connectivity. In addition, reduced variation during infancy is associated with neurodevelopmental disorders in later life and reduced intelligence at school age. Variability denotes the child's ability to select from the repertoire of movements the strategy that suits the situation best. In this prospective, assessor-blinded cohort study, we address the question whether ovarian hyperstimulation and/or the in vitro procedure affect movement variation during infancy. Material and Methods: Singletons born following IVF with conventional controlled ovarian hyperstimulation (COH-IVF, n = 68), following IVF in a modified natural cycle (MNC-IVF, n = 57) and following natural conception born to subfertile couples (Sub-NC, n = 90) were assessed with the IMP at 4, 10 and 18 months. The assessment resulted in a total IMP score and 5 domain scores: variation (i.e. the size of movement repertoire), variability (i.e. the ability to select motor strategies), symmetry, fluency and performance. Primary outcome was the domain score variation. Outcome variables were analyzed with a mixed effects model. Results: The mixed model indicated an overall effect of treatment on variation (p Conclusions: The preliminary data suggest that ovarian hyperstimulation may be associated with reduced movement variation in infancy. These findings stress the need to carefully monitor neurodevelopment in IVF offspring