Standard growth charts and parameters do not apply to all children. They do not apply to children who are born prematurely or with a genetic defect such as:
- Williams Syndrome
- Down Syndrome
- Turner Syndrome
- Prader-Willi syndrome
- Other chromosomal abnormalities
Growth for premature babies once they leave the hospital should be monitored more frequently than a full term baby. This may be as often as weekly for the first few weeks after discharge and spread out over time to eventually be on the regular doctor visit schedule as other children.Pediatricians make corrections for gestational age for weight through 24 months of age, for height through 40 months of age, and for head circumference through 18 months of age. The Fenton preterm infant growth chart is usually used until the infant is 44 to 48 weeks corrected gestational age. After that point, Pediatricians typically use the growth curve from the World Health Organization (WHO). It is important to catch delays in growth quickly to prevent increasing the amount of catch-up growth that is needed and to prevent growth failure.
Genetic syndromes such as Trisomy 21, Turner's, or Prader-Willi will have their own path of anticipated growth. These growth curves help to assess a child's growth by comparing it to those who have the same syndrome. They can help to determine when an intervention may be needed, such as growth hormone treatment in the case of Turner's Syndrome. There are many birth defects for which a widely accepted growth chart may not be available. This is why it is very important to regularly see a specialist who can help to monitor growth to ensure it is optimal.