Background and aims Nearly three quarters of preterm infants are 34 to 36 weeks gestational age (GA), or late preterm (LPT). LPT children are at significantly greater risk for neurological, language and communication delays, social and emotional problems, and attention-deficit/hyperactivity disorder than children born full term. Developmental screening and early intervention may mitigate these risks. Little is known about early patterns of risk across developmental domains in the LPT group as this grouping has been consistently defined only recently. The purpose of this study was to describe patterns of development in Canadian children born LPT.

Methods Mothers of 61 LPT infants (57% male) completed the Ages and Stages Questionnaire 3^rd edition (ASQ-3) when their child was 4, 8 and 18 months corrected age. The 30-item ASQ-3 addresses communication, gross motor, fine motor, problem solving, and personal social functioning. Referral cut-off is < 2 SD below the mean, and monitoring is required between 1 and 2 SD below.

Results There was a clear inverse relationship between GA and proportion of children requiring referral or monitoring over time. For 34 weeks GA, 67% to 83% of children demonstrated risk in one or more domains; for 35 weeks, the proportion was 50% to 65%; and still lower for 36 weeks (40% to 54%). Communication and gross motor were the most problematic domains.

Conclusion The ASQ-3 may be useful to capture delays in LPT children, particularly in communication and gross motor domains. These results have implications for early childhood developmental assessment and intervention services.