What’s Up Docs? Article

Renee C. Wachtel, MD, FAAP

Posted June 5, 2024


Fortunately, the answer is now available, to some extent. A study published in the April 2024 issue of Pediatrics (Sudry, T et al Sex Specific Developmental Scales for Surveillance. 153(4) e2023062483) addresses the issue of whether there are sex-specific differences in attainment of developmental milestones and evaluates the clinical need for separate sex-specific scales. 

As we know, developmental surveillance conducted routinely in well child visits is fundamental for the detection of children at risk for developmental delay. This study was a cross-sectional, nationwide retrospective study using data from about 1000 maternal child health clinics including 839,574 children birth to age 6 years involved in 309,181 well child visits. Large amounts of data were obtained. They excluded 195,616 children with “abnormal developmental potential”. They then used the data to determine whether sex specific differences in 59 developmental milestones from 4 developmental domains existed, and whether a significant gap existed between males and females. 

What did they find? They found that using a unified scale (both sexes combined), compared to sex-specific scales, resulted in the potential missing of females at risk for developmental delay (19.3% of failed assessments) and the over-diagnosis of males not requiring further evaluation (5.9% of failed assessments). Or put another way, males do attain developmental milestones later than females, and we over-call delay in males and under-call delay in females using a unified (non-sex specific) developmental scale. 

Based upon their data, they have constructed sex-specific developmental milestone scales, showing attainment of the milestones by 75%, 75-90% and 95% of children between birth and 6 years.  However, if you look at the individual milestones carefully, you will see that for most milestones, there is little differences between when 75% of each sex attain each milestone. 

Insert figures 3  A and B here. 

Why is this important? It reinforces the importance of  developmental surveillance during early childhood, and updates the expectations of specific milestone attainment for both sexes. And it enables pediatricians to answer the question: do boys develop slower than girls?

Let me know if you need further information, and please join our CAC1 AAP Committee on Development and Behavior.