Laterality in five-year-olds conceived by intracytoplasmic sperm injection, standard in vitro fertilisation and natural conception:: a European study

Objective To assess laterality in a group of European children conceived with the help of assisted reproductive therapy, or naturally conceived. Design Prospective cohort study. Setting Five European countries. Population A total of 1525 five-year-old children divided into three groups according to conception status: naturally conceived; intracytoplasmic sperm injection (ICSI); in vitro fertilisation (IVF) group. Methods All children were assessed using the McCarthy Scale of Children's Abilities (Motor Scale) with additional items using a comb, a spoon and an indirect measure was made of the parental handedness scores, using a questionnaire. Main outcome measures Child handedness for drawing and writing. Results Observed handedness did not differ significantly between natural conception, IVF and ICSI in girls or boys, except for ICSI-conceived girls, fewer of whom were left-handed than the naturally conceived controls, 7.0%versus 12.4% (P < 0.05), however, this was close to the population norm of 8%. The degree of parental handedness did not significantly vary in the three groups. Conclusions Laterality, as assessed by handedness, may be marginally less common in girls conceived with assisted reproductive therapies than with children conceived naturally.