The Groningen ART cohort study: the effects of ovarian hyperstimulation and the IVF laboratory procedures on neurological condition at 2 years

Abstract

Up to 4% of children are born following assisted reproduction techniques (ART) yet relatively little is known on neurodevelopmental outcome of these children after 18 months of age. Only a limited number of long-term follow-up studies with adequate methodological quality have been reported. Our aim was to evaluate the effects of ovarian hyperstimulation, IVF laboratory procedures and a history of subfertility on neurological condition at 2 years. Singletons born after controlled ovarian hyperstimulation IVF (COH-IVF, n = 66), modified natural cycle IVF (MNC-IVF, n = 56), natural conception in subfertile couples (Sub-NC, n = 87) and in fertile couples (reference group, n = 101) were assessed (using Hempel approach) by neurological examination at 2 years of age. This resulted in a neurological optimality score (NOS), a fluency score and the prevalence of minor neurological dysfunction (MND). Primary outcome was the fluency score, as fluency of movements is easily affected by subtle dysfunction of the nervous system. Fluency score, NOS and prevalence of MND were similar in COH-IVF, MNC-IVF and Sub-NC children. However, the fluency score (P < 0.01) and NOS (P < 0.001) of the three subfertile groups were higher, and the prevalence of MND was lower (P = 0.045), than those in the reference group. Neurological condition of 2 year olds born after ART is similar to that of children of subfertile couples conceived naturally. Moreover, subfertility does not seem to be associated with a worse neurological outcome. These findings are reassuring, but we have to keep in mind that subtle neurodevelopmental disorders may emerge as children grow older.