When should a hormone replacement therapy be considered in functional

Hormone replacement therapy (HRT) should be considered in a 15-year-old adolescent with functional hypothalamic amenorrhea (FHA) when lifestyle and underlying causes such as stress, weight loss, or excessive exercise have been addressed but menstruation has not resumed and there is concern for bone health. FHA is a common cause of primary or secondary amenorrhoea in adolescents, often related to energy deficiency and hypothalamic suppression NICE CKS. The initial management involves addressing underlying factors through lifestyle modification and psychological support, including referral to specialist services if an eating disorder is suspected NICE CKS,NICE NG69.

When these measures fail to restore menstrual cycles and the adolescent has evidence of low bone mineral density (BMD) or is at risk of long-term hypoestrogenism complications, consideration of HRT, preferably using physiological transdermal estradiol with cyclic progesterone, is recommended by recent evidence to improve bone density while mimicking natural hormone levels Efthymiadis et al. 2026,NICE NG69. Oral HRT and combined oral contraceptives (COCP) have not shown significant benefit on BMD in FHA compared to transdermal HRT Efthymiadis et al. 2026.

Additionally, specialist paediatric or endocrinological advice should be sought prior to starting hormonal treatment for bone health to ensure appropriate dosing and monitoring, given the adolescent’s ongoing growth and pubertal development needs NICE NG69. Close monitoring of growth, bone density, and response to treatment is essential during therapy NICE NG69.

HRT in this setting is not primarily for symptom control as in menopause but to provide sex steroid replacement to prevent complications of prolonged hypoestrogenism, such as poor bone development, and to support normal pubertal development NICE CKS,NICE NG69. The choice of hormone regimen should consider the lowest effective dose with cyclical progesterone to protect the endometrium if the uterus is intact SmPC Conjugated,SmPC Conjugated.

In summary, HRT should be considered in a 15-year-old with FHA if lifestyle interventions fail to restore menstrual function and there is evidence or high risk of adverse effects from estrogen deficiency, particularly on bone health. This should be coordinated with multidisciplinary support including endocrinology and eating disorder services as appropriate NICE CKS,NICE NG69,Efthymiadis et al. 2026.