Functional hypothalamic amenorrhoe in an adolescent age 15

Management and Investigation Approach for Functional Hypothalamic Amenorrhoea in a 15-year-old Adolescent:

Functional hypothalamic amenorrhoea (FHA) in adolescents commonly results from factors such as stress, significant weight loss, excessive exercise, and eating disorders, presenting as secondary amenorrhoea but may also be a cause of primary amenorrhoea if menstruation has not been established by age 15 with normal secondary sexual characteristics NICE CKS.

A thorough clinical history and examination should be performed to assess contributing factors including psychosocial stressors, weight changes, and exercise habits NICE CKS. Initial investigations in primary care should include serum hormone measurements such as prolactin, thyroid-stimulating hormone, follicle-stimulating hormone (FSH), luteinizing hormone (LH), and oestradiol to exclude other endocrine causes NICE CKS. If signs of androgen excess exist, total testosterone should be measured NICE CKS. Pelvic ultrasound may be considered to assess anatomical causes if clinically indicated NICE CKS.

Referral to specialists is needed to exclude other hypothalamic or pituitary pathology, particularly if initial investigations are abnormal. In suspected eating disorders contributing to FHA, prompt referral to an age-appropriate community eating disorders service is essential NICE CKS,NICE NG69.

Management primarily focuses on reversing the underlying energy deficiency by promoting a moderate increase in food intake and modest weight gain, and reducing excessive exercise to restore energy availability, since these interventions can reverse energy deficiency-induced menstrual disturbances in adolescents NICE CKS,Williams et al. 2026. Restoring menses may require multiple consecutive regular menstrual cycles to achieve normal ovarian steroid hormone levels and ovulation Williams et al. 2026. Psychological stress should also be addressed as it impacts individual susceptibility to FHA Williams et al. 2026.

In adolescents with associated low bone mineral density, assessment including bone density scanning (using size-corrected measures such as bone mineral apparent density) after one year of underweight or earlier if bone symptoms occur is recommended NICE NG69. Hormonal treatment with physiological doses of transdermal 17-beta-estradiol (with cyclic progesterone) may be considered in young women (13 to 17 years) with long-term low weight and established low bone density after specialist advice. Routine oral estrogen therapy is not routinely recommended NICE NG69.

The focus of treatment is multidisciplinary, involving endocrinology, eating disorder services, and psychological support to optimize energy status, menstrual function, and bone health, with an understanding that recovery is gradual and may necessitate prolonged monitoring NICE CKS,NICE NG69,Williams et al. 2026.