Use of Developmental Milestones in Pediatric Residency Training and Practice: Time to Rethink the Meaning of the Mean

The monitoring of young children’s development during preventive care visits to identify children whose development is atypical or concerning for delay is a core part of pediatric training and practice. Monitoring and screening of young children’s development are supported by guidelines from the American Academy of Pediatrics (AAP),1,2 which recently issued revised recommendations for developmental surveillance to include screening of all children at specific health supervision visits (the 9-, 18-, and 30- (or 24-) month visits).2 Federal legislation in the form of the Individuals with Disabilities Education Act Part C supports the early identification and treatment of developmental problems in young children.3 Early identification of children with developmental delays or at risk of delay allows for referral to early intervention services, which have been shown to improve developmental and behavioral outcomes.4–6 Studies suggest that while certain, less common types of developmental conditions, specifically those associated with neonatal risk factors, motor delays, and genetic conditions, are typically identified in a timely way by pediatricians, more prevalent conditions including speech and language delay, milder cognitive disabilities, and atypical behaviors may only be identified later in childhood or even at school entry, often outside the medical system.7,8 Use of validated developmental screening tools can increase detection of developmental delays.9–13 There has been limited adoption of the systematic use of developmental screening tools in practice, however, with multiple barriers identified to their use.14,15 Comparison of a child’s current developmental skills to milestone data remains the most frequently reported method of developmental surveillance for physicians in practice, in conjunction with the clinical assessment and the physical examination of the child.14,15 It is therefore critical to understand the validity, utility, and limitations of developmental milestones as a tool in developmental surveillance. In this commentary, I recommend moving away from a traditional focus on presentation of the 50th percentile for developmental skills to a varied presentation of information with criteria based on clinical and training purposes. This information is important for developmental-behavioral pediatricians who are charged with teaching pediatric residents about child development and developmental screening and who may author chapters on child development in pediatric textbooks. In order to evaluate how developmental milestones are currently presented in academic texts, I undertook a review of chapters on child development or developmental disabilities in standard pediatric texts16,17; a popular pediatric reference guide18; texts in developmental-behavioral pediatrics,19–22 guidelines on health supervision from the AAP23 and Bright Futures,24 and a parent guide published by the AAP.25 In addition, I reviewed guidance from the American Board of Pediatrics on the topic of child development for the recertification examination in general pediatrics.26 The texts were chosen as a representative rather than exhaustive sample of published educational materials available for training and practice in the United States, based on my experiences as a trainee and faculty member in three pediatric training programs, and the recommendations of colleagues in the field. Chapters on child development or developmental disabilities were reviewed for content, with an emphasis on presentation of age-skill material (milestones) and original sources for milestone data. Original sources of milestone data cited in the references were reviewed.