Developmental checks and delays

📈Development comes in ranges

Milestones such as walking or first words have a wide normal range, not a single average month. It is common for one area to be a bit ahead and another a bit behind. What matters is that your child keeps gaining new skills and moving forward.

For babies born prematurely (before 37 weeks), development is judged by corrected age, based on the due date rather than the birth date, until about age 2. For example, a 6-month-old born 2 months early is compared with a typical 4-month-old.

📝Korea's infant health checkups and the K-DST

In Korea, the national infant and child health screening program offers free checkups at set ages from 14 days to 71 months. From around the 4-month checkup, development is assessed with the Korean Developmental Screening Test for Infants and Children (K-DST).

The K-DST is a screening questionnaire that parents fill out based on their child's everyday behavior, covering gross motor, fine motor, cognition, language, social skills and self-help. It is completed in advance or at the clinic, and the doctor reviews the results with you. If you are unsure whether your child can do something, try it at home first and answer honestly for the most accurate result.

Results usually fall into levels such as "typical for age," "follow-up recommended" and "further evaluation recommended." Screening is not a diagnosis; it sorts out whether a closer look is needed.

• Typical for age: keep checking at the next checkup.
• Follow-up recommended: do activities that encourage the skill and recheck soon.
• Further evaluation recommended: you will be referred for a detailed developmental assessment by pediatrics, rehabilitation medicine or child psychiatry. There is financial support for these assessments, so ask the National Health Insurance Service or your public health center whether you qualify.

🚩Red flags that need a doctor

If you notice any of the following, see a pediatrician without waiting for the next checkup (based on CDC, AAP and similar guidance).

• At any age: losing words, behaviors or skills your child once had (regression)
• At 2 to 3 months: not responding to sounds or faces, or not making eye contact
• Around 6 months: rarely smiling or responding with sounds
• At 12 months: no babbling, rarely responding to their name, or no gestures like pointing or waving
• At 16 to 18 months: no meaningful words at all
• At 18 months: not walking
• At 2 years: not putting two words together (such as "more milk")
• Clear differences between the left and right side, such as using only one arm or leg, or persistently little eye contact

🗣️When talking is late

• Check hearing first. Even after passing the newborn hearing screening, hearing problems can develop later, for example from ear infections.
• Also look at understanding (following simple instructions), gestures, eye contact and play. Whether only speech is late while understanding and social skills are fine is an important clue.
• At home, talk in short, simple words about what interests your child, and repeat their words back slightly expanded ("milk" → "more milk").
• Cut screen time and build conversation through picture books, songs and play.
• Growing up with two languages does not cause speech delay. Talk richly in whichever language feels natural to you.

🤲Early intervention and where to get help

For developmental delays or autism spectrum disorder, the earlier they are found and support such as speech, occupational or play therapy begins, the greater the benefit. Therapy can often start even before a diagnosis is confirmed.

In Korea, support includes funding for detailed assessments based on health checkup results and developmental rehabilitation service vouchers for children with a diagnosed disability. Eligibility and amounts change every year, so check the latest on Bokjiro, Government24, the National Health Insurance Service, or at your community center or public health center.

💬FAQ