Delayed Puberty: Definition, Evaluation Timeline, and When to Refer

Delayed puberty is defined as absence of secondary sexual characteristics by an age >2–2.5 SD above population mean.

Diagnostic Thresholds

• Girls: No breast development (thelarche) by age 13; no menarche by age 15 (or >5 years after thelarche).
• Boys: No testicular enlargement (>4 mL or >2.5 cm length) by age 14; no pubertal progression by age 16.

Common Causes

• Constitutional Delay of Growth and Puberty (CDGP): Most common (especially boys). Family history of "late bloomers." Normal growth velocity, bone age delayed. Self-limited.
• Hypogonadotropic Hypogonadism: Kallmann syndrome (anosmia), functional (excess exercise, eating disorders, chronic illness, stress), pituitary/hypothalamic tumors, infiltrative diseases.
• Hypergonadotropic Hypogonadism (Primary Gonadal Failure): Turner syndrome (45,X), Klinefelter (47,XXY), gonadal dysgenesis, chemo/radiation damage, autoimmune, infections (mumps orchitis).
• Chronic Disease: IBD, CF, CKD, sickle cell, malnutrition.
• Endocrine: Hypothyroidism, Cushing's, hyperprolactinemia.

Initial Evaluation

• Growth chart (height velocity, bone age X-ray).
• LH, FSH, estradiol/testosterone, TSH, prolactin, IGF-1.
• Karyotype if Turner/Klinefelter suspected.
• MRI brain if hypogonadotropic (rule out structural lesion).

Management

• CDGP: Reassurance, monitor. Low-dose sex steroid priming if psychosocial distress (testosterone 50 mg IM monthly × 3–6; estrogen patch).
• Organic Causes: Treat underlying condition; hormone replacement (estrogen/progesterone or testosterone) to induce puberty and maintain bone/sexual function.

Early referral to pediatric endocrinology optimizes final height, bone health, and psychosocial well-being.