Developmental Screening at Well-Child Visits: What Parents Should Know

Screening vs. evaluation: a key distinction

These two terms are sometimes used interchangeably by families, but they mean different things in pediatric practice. Screening is a quick, population-level tool designed to identify children who may have a developmental concern — it is sensitive (catches many who need follow-up) but not specific (also flags some children who turn out to have typical development). A developmental evaluation is a comprehensive, individualized assessment done by a specialist or multidisciplinary team to determine whether a specific condition is present and to what degree 1Ref 1American Academy of Pediatrics, Council on Children with Disabilities (2020).Promoting Optimal Development: Identifying Infants and Young Children With Developmental Disorders Through Developmental Surveillance and Screening.AAP recommendation for standardized developmental screening at the 9-, 18-, and 30-month well-child visits and autism-specific screening at 18 and 24 months for all children.

A screening result — positive or negative — is not a diagnosis. It is a sorting step.

When and how developmental screening happens

The American Academy of Pediatrics recommends that all children receive developmental and behavioral screening at the 9-, 18-, and 30-month well-child visits (or 24-month if 30-month is not feasible) 1Ref 1American Academy of Pediatrics, Council on Children with Disabilities (2020).Promoting Optimal Development: Identifying Infants and Young Children With Developmental Disorders Through Developmental Surveillance and Screening.AAP recommendation for standardized developmental screening at the 9-, 18-, and 30-month well-child visits and autism-specific screening at 18 and 24 months for all children. Autism-specific screening is recommended at 18 and 24 months for all children, not just those with obvious concerns 1Ref 1American Academy of Pediatrics, Council on Children with Disabilities (2020).Promoting Optimal Development: Identifying Infants and Young Children With Developmental Disorders Through Developmental Surveillance and Screening.AAP recommendation for standardized developmental screening at the 9-, 18-, and 30-month well-child visits and autism-specific screening at 18 and 24 months for all children2Ref 2Centers for Disease Control and Prevention (2024).Learn the Signs. Act Early. — Developmental Milestones.CDC milestone framework tracking communication, motor, and social development from 2 months to 5 years; CDC recommends autism screening at 18 and 24 months.

In practice, most providers use parent-completed questionnaires — the most common include the Ages and Stages Questionnaire (ASQ), the Parents' Evaluation of Developmental Status (PEDS), and the Modified Checklist for Autism in Toddlers (M-CHAT). Parents answer questions about what their child does at home, which they are often better positioned to report than brief in-office observation.

What happens after a positive screen

If a child screens positive on a developmental questionnaire, the next step is typically a more detailed conversation with the pediatrician, and often a referral — either to the early intervention system (for children under 3), to a developmental pediatrician, to a speech-language pathologist, or to another specialist depending on the area of concern 1Ref 1American Academy of Pediatrics, Council on Children with Disabilities (2020).Promoting Optimal Development: Identifying Infants and Young Children With Developmental Disorders Through Developmental Surveillance and Screening.AAP recommendation for standardized developmental screening at the 9-, 18-, and 30-month well-child visits and autism-specific screening at 18 and 24 months for all children.

A positive screen does not mean a child definitively has a delay or disorder. In screening research, false positives are common — some children who screen positive turn out to be developing typically when evaluated in more depth. This is by design: it is better to over-refer than to miss a child who needs support.

What a negative screen does and does not mean

A negative (passing) screen at a given visit means the questionnaire did not flag the child for follow-up at that time. It does not permanently rule out developmental concerns — development changes rapidly in early childhood, and a screen is a snapshot.

Parents who have concerns after a negative screen — for example, if a child loses a skill they previously had, or if a parent has a gut feeling something is different — should bring those concerns to the pediatrician regardless of a passing screen 2Ref 2Centers for Disease Control and Prevention (2024).Learn the Signs. Act Early. — Developmental Milestones.CDC milestone framework tracking communication, motor, and social development from 2 months to 5 years; CDC recommends autism screening at 18 and 24 months. Clinical concern always overrides a passing questionnaire.

Key language milestones that inform screening

Developmental screening questionnaires flag children who may not be reaching age-appropriate milestones. For speech and language, widely used benchmarks include: a first word by 12 months, 10 or more words by 18 months, and at least 50 words plus two-word combinations (such as 'more milk' or 'daddy go') by 24 months 3Ref 3American Speech-Language-Hearing Association (2023).Late Language Emergence (Practice Portal).ASHA guidance on identifying language concerns in children at 24 months, including the 50-word and two-word-combination threshold as a widely used diagnostic marker4Ref 4National Institute on Deafness and Other Communication Disorders (2023).Speech and Language Developmental Milestones.NIH milestones for speech and language development from birth through age 5, including vocabulary expectations at 12–24 months. The CDC's 'Learn the Signs. Act Early.' program provides milestone checklists — organized by age from 2 months through 5 years — that families can use to track development and bring structured observations to well-child visits 2Ref 2Centers for Disease Control and Prevention (2024).Learn the Signs. Act Early. — Developmental Milestones.CDC milestone framework tracking communication, motor, and social development from 2 months to 5 years; CDC recommends autism screening at 18 and 24 months.

Why universal screening matters

Many developmental conditions — including autism spectrum disorder, developmental language disorder, and others — are more effectively addressed when identified early, while the brain's plasticity is highest 1Ref 1American Academy of Pediatrics, Council on Children with Disabilities (2020).Promoting Optimal Development: Identifying Infants and Young Children With Developmental Disorders Through Developmental Surveillance and Screening.AAP recommendation for standardized developmental screening at the 9-, 18-, and 30-month well-child visits and autism-specific screening at 18 and 24 months for all children. Universal screening at every well-child visit ensures that children are not missed simply because their parents did not know what to look for or were waiting for a child to 'grow out of it.' Screening also surfaces disparities: children from lower-income families and children of color are identified later, on average, for developmental differences — in part because of reduced specialist access and barriers in screening tools. Universal, standardized screening at primary care visits helps narrow that gap 1Ref 1American Academy of Pediatrics, Council on Children with Disabilities (2020).Promoting Optimal Development: Identifying Infants and Young Children With Developmental Disorders Through Developmental Surveillance and Screening.AAP recommendation for standardized developmental screening at the 9-, 18-, and 30-month well-child visits and autism-specific screening at 18 and 24 months for all children.