Mid Parental Height Formula

A mid-parental height calculator is a tool that can be used to predict the future height of a child. To predict the adult height of a child, we can use a method called mid-parental height. To calculate the mid-parental height, we take the average of the mother’s height and the father’s height.

From there, we can use a growth chart to predict the child’s final adult height. This method is not perfect, but it gives us a general idea of how tall a child is likely to be as an adult.

Prediction tool or calculator for mid-parental height

A child’s adult height potential can be estimated using the mid-parental height formula.

Plot the child’s estimated growth percentiles

The estimated mid-parental height should be plotted at the 20-year mark. Of note, the confidence intervals for the mid-parental height estimate should be within 2 inches or 5 centimeters of the predicted value. The child’s plotted growth rate should be within the 3rd and 97th percentiles.

When is further evaluation required?

For patients with confirmed short stature, a detailed evaluation is required. The differential diagnoses of short stature will be reviewed next.

Common Causes of Short Stature and Growth Failure

Normal Variants of Growth

• Familial short stature
• Constitutional delay in growth and puberty (CDGP)

Systemic Disorders

Endocrine Disorders

• Growth hormone deficiency
• Hypothyroidism
• Cortisol excess (endogenous or exogenous)

Non-Endocrine Disorders

• Malnutrition
• Malabsorptive diseases
• Genetic syndromes:
  • Turner syndrome
  • Noonan syndrome
  • Achondroplasia
  • SHOX gene haploinsufficiency
• Chronic inflammatory conditions (e.g., inflammatory bowel diseases)
• Chronic medical conditions (e.g., asthma treated with inhaled steroids)

Children who fall above or below the normal percentiles should undergo a detailed growth evaluation (read this guide to evaluating short stature).

The following tests should be ordered during the evaluation of short stature.

• Complete blood count/hemogram/full blood count
• Bone age (Plain skeletal radiograph)
• Urinalysis/Urine Routine Examination
• Stool for parasites, occult blood, and fecal fat
• Complete Metabolic Panel
• TSH and free T4
• Karyotype analysis in girls
• Celiac panel with possible duodenal biopsy
• IGFBP-3 and IGF-1
• Growth hormone stimulation test 

Idiopathic Short Stature: Definition and Considerations

Idiopathic short stature (ISS) is defined as a height standard deviation score (SDS) ≤ -2.25 (≤1.2nd percentile) in pediatric patients where diagnostic evaluations exclude other identifiable causes of short stature, and growth hormone (GH) levels exceed 10 nanograms per milliliter following physiological or pharmacological stimulation. While this definition offers a static criterion for ISS, it fails to account for the dynamic nature of growth patterns and the potential for evolving causes of GH deficiency. Longitudinal follow-up is critical to accurately diagnose and manage ISS, as growth abnormalities may emerge over time. Through three illustrative cases, we underscore the importance of longitudinal evaluation to establish a child’s growth trajectory, identify late-onset GH deficiencies, and exclude non-GH-related factors such as malabsorptive diseases, familial short stature, constitutional pubertal delay, Turner syndrome, and SHOX gene haploinsufficiency. This approach ensures an accurate diagnosis of growth failure of unknown etiology (GFUE).

The concept of idiopathic short stature (ISS) evolved during the 1980s following an observational study reporting growth outcomes in children treated with growth hormone, including those with normal peak GH responses to stimulation. This group, initially referred to as having “constitutional short stature,” was later redefined under the term ISS. According to guidelines established by the Pediatric Endocrine Society, ISS is characterized by a height SDS ≤ -2.25 (≤1.2nd percentile) in children whose diagnostic evaluation excludes other causes of short stature and whose GH levels exceed 10 nanograms per milliliter after stimulation.

Evaluating children with short stature requires prolonged observation to establish growth patterns and rule out non-GH-related factors that may impair growth. Tools such as the Centers for Disease Control and Prevention (CDC) growth charts (percentiles 3rd–95th) in the United States and the World Health Organization (WHO) growth charts (percentiles 2.3rd–97.7th) globally are utilized to monitor growth trajectories. While normal growth patterns vary widely, conditions that contribute to short stature are equally diverse. These include normal growth variants such as familial short stature and constitutional delay in growth and puberty, as well as systemic conditions like malabsorptive diseases, Turner syndrome, and SHOX gene haploinsufficiency.

The initial diagnostic workup performed by pediatric endocrinologists focuses on identifying the underlying cause of poor growth. Importantly, malnutrition remains the leading global cause of growth failure, highlighting the need for context-specific evaluations. This comprehensive approach ensures that ISS and other growth-related conditions are accurately diagnosed and appropriately managed.

Growth Hormone Therapy for Idiopathic Short Stature: A Controversial Approach

The approval of growth hormone (GH) therapy for idiopathic short stature (ISS) by the Food and Drug Administration (FDA) in 2003 remains a subject of debate two decades later. ISS is not universally accepted as an indication for GH treatment. While the use of GH for ISS is approved in regions such as the United States, Canada, and Latin America, it has not been sanctioned in the European Union or Japan. This discrepancy underscores the ongoing controversy surrounding the definition and treatment of ISS.

Concerns about the definition of ISS have been raised by many investigators, including our group. The current definition does not explicitly exclude patients with normal growth variants, such as constitutional growth delay or familial short stature, as noted in the Pediatric Endocrine Society’s consensus statement. By focusing solely on stature (height standard deviation score ≤ -2.25) rather than growth patterns and growth failure, the definition leaves GH treatment vulnerable to criticism as a mere height-enhancing intervention. For example, a child whose height decelerates from the 75th to the 25th percentile without any identifiable cause would not meet the ISS criteria, despite clear concerns about their growth trajectory.

We have argued that cases such as these should be classified under a broader category of idiopathic growth failure (IGF), emphasizing the importance of addressing growth failure rather than just height. However, given the overlap of IGF with the abbreviation for Insulin-Like Growth Factor, we propose the term Growth Failure of Unknown Etiology (GFUE). This terminology more accurately reflects the diagnostic and therapeutic focus on unexplained growth failure rather than stature alone.

To illustrate the complexities and diagnostic dilemmas in managing short stature, we present three cases of children with similar growth patterns and normal responses to initial GH stimulation testing using two provocative agents. Although these cases might initially be classified as ISS, they demonstrate markedly different clinical outcomes, highlighting the importance of a nuanced approach to diagnosis and management.

References

Tanner JM, Goldstein H, Whitehouse RH. Standards for children’s height at ages 2-9 years allowing for heights of parents. Arch Dis Child. 1970 Dec;45(244):755-62. doi: 10.1136/adc.45.244.755.