Motor delay - An early and more common "red flag" in girls rather than boys with autism spectrum disorder.

BACKGROUND

Autism and intellectual disability may coincide and be preceded by global developmental delay or by motor delay.

HYPOTHESIS

Motor delay in the context of global developmental delay is an initial "red flag" for ASD, with added risk in girls.

OBJECTIVE

To assess early developmental milestones in girls with ASD as compared to diagnosed boys, considering prematurity risk.

METHOD

Developmental milestones in a cohort of 467 children with ASD - diagnosed at mean age of 3.4 years (SD = 2.2) - were analyzed according to gender and prematurity risk.

RESULTS

111 girls (24 %), 356 boys (76 %), presented with motor milestones acquisition grossly within the normal range. However, there was a shift towards acquisition of walking being at the later end of the norm range, with this shift being more prominent in girls. 60 % of girls and 47 % of boys with ASD had motor delay and 49 % of girls and 36 % of boys had global developmental delay. The extent of the delays was greater in the prematurity subgroup.

CONCLUSION

Global delay of early milestones occurred in half of children with ASD and in 60 % of girls with ASD. Delayed acquisition of independent walking is relatively more common in girls subsequently diagnosed with ASD.