Catch-up growth: definition, mechanisms, and models.

Area of Science:

• Pediatrics
• Endocrinology
• Human Growth and Development

Background:

• Catch-up growth is a physiological response to transient growth inhibition, aiming to restore normal growth trajectory.
• Distinguishing catch-up growth from the pubertal growth spurt and defining its completeness can be challenging.
• Intrauterine growth retardation often triggers a process termed catch-up growth, though it may not fully meet established criteria.

Purpose of the Study:

• To clarify the definition and characteristics of catch-up growth.
• To differentiate catch-up growth from other growth phenomena like the pubertal spurt.
• To evaluate methods for assessing the completeness of catch-up growth.

Main Methods:

• Analysis of height velocity and height standard deviation scores over time.
• Comparison of growth patterns in various pediatric populations, including those with intrauterine growth retardation.
• Review of proposed mechanisms for catch-up growth, including neuroendocrine and growth plate hypotheses.

Main Results:

• Height velocity exceeding normal limits for at least one year characterizes catch-up growth.
• Height standard deviation score changes are more precise than height velocity for evaluating catch-up growth.
• Complete catch-up growth is probable if final height falls within the target range, and in groups, it results in mean final height near the mean target height.
• Growth hormone therapy-induced growth velocity is termed catch-up growth in GH deficiency but growth enhancement in other conditions.

Conclusions:

• Catch-up growth is a complex process with varying degrees of completeness.
• Accurate assessment of catch-up growth requires careful consideration of height standard deviation scores.
• Current hypotheses on catch-up growth mechanisms require further investigation and validation.