The family, of average height, noticed both girls were growing unusually tall. In September, they took the girls for checkups at Tam Anh General Hospital in Ho Chi Minh City in preparation for the new school year. Doctor Lam Boi Hy, a pediatrician, noted that the average height for an 8-year-old girl is around 120 cm, and for a 6-year-old, it's 110 cm. Both girls were 20-25 cm taller than average and showed breast development.

An X-ray revealed Ngoc Anh's bone age to be 11, three years older than her chronological age. A blood test showed her luteinizing hormone (LH) level at 1.9 IU/L (normal is below 0.3 IU/L), indicating her pituitary gland was activated and producing gonadotropin, which stimulates the ovaries to produce reproductive hormones. As Ngoc Anh had already begun menstruating, she was diagnosed with central precocious puberty and prescribed medication to suppress the pituitary gland's release of LH and follicle-stimulating hormone (FSH).

My Anh's bone age was 8, two years older than her actual age. Her LH level was 0.9 IU/L, also above normal. She was hospitalized for observation and underwent a gonadotropin-releasing hormone (GnRH) stimulation test to assess pituitary function. She was also diagnosed with central precocious puberty.

Doctor Hy explained that both girls require monthly or quarterly injections to suppress puberty until they are 11, allowing puberty to occur naturally. The medication will halt breast development and menstruation, slow bone maturation to match their chronological age, and maximize their adult height.

Doctor Hy examines a patient with precocious puberty. Photo illustration: *Tam Anh General Hospital*

Precocious puberty is the early development of secondary sexual characteristics before the typical age. Signs include breast growth, pubic or underarm hair, menstruation, and a rapid height increase that surpasses peers but can cease prematurely, resulting in shorter adult stature.

The condition is classified as either central or peripheral precocious puberty. Central, the most common type, occurs when the brain prematurely releases hormones, triggering the normal puberty process too early. Peripheral precocious puberty happens when sex hormones are produced by the adrenal glands, ovaries, or testes due to tumors or other health issues, not triggered by the brain. Genetics can also play a role; if a girl's mother or sister experienced early menstruation, she may also be at risk. Children with the condition may experience confusion, self-consciousness, or feelings of being different from their peers.

Doctor Hy emphasized the importance of early detection and treatment before the age of 8 (Ngoc Anh's case was considered relatively late) for optimal results. Central precocious puberty is treated with medication, while peripheral precocious puberty requires addressing the root cause, such as surgical removal of tumors or cysts.

Doctor Hy recommends regular checkups to assess for signs of precocious puberty. Doctors may order blood tests to measure sex hormone levels (LH, FSH), bone age X-rays, ultrasounds, or MRIs to determine the cause.

Dinh Lam

*Names have been changed.