Basal and FSH-stimulated Inhibin B in Precocious Puberty.

Objective: To evaluate the role of basal and follicle-stimulating hormone (FSH)-stimulated inhibin B in differentiating premature thelarche from gonadotropin-dependent precocious puberty (GDPP).

Methods: This was a prospective interventional study. Basal and FSH-stimulated inhibin B levels were estimated in girls presenting with thelarche < 8 years age (n = 10), healthy girls with normal pubertal development (pubertal control) (n = 8) and healthy prepubertal girls (prepubertal control) (n = 7). Girls with early puberty were classified as premature thelarche or GDPP based on GnRH agonist stimulation test.

Results: Median (IQR) basal inhibin B levels (pg/mL) in premature thelarche was 5.42 (2.91, 30.58) and FSH-stimulated inhibin B was 236.72 (111.53, 4431.73) (P = 0.043). Median (IQR) basal inhibin B in GDPP was 64.11 (24.96, 792.45) pg/mL and FSH-stimulated inhibin B was 833.66 (500.11-1266.18) pg/mL (P = 0.043). Basal inhibin B was discriminatory between GDPP and premature thelarche (P = 0.032). Median (IQR) basal inhibin B in prepubertal and pubertal controls was 20.36 (9.61, 29.12) and 75.48 (58.55, 165.55) pg/mL, respectively.

Conclusion: Basal inhibin B is useful in differentiation of premature thelarche from GDPP while the role of FSH-stimulated inhibin B needs to be further explored in large sample size.