Conditions · Obstetrics and gynecology
Functional hypothalamic amenorrhoea !
Periods stop because the brain lowers its signals to the ovaries, usually from too little food, too much exercise or stress. It is reversible.
Updated 2026-11-01
Structures involved
Tap one to see what it is and open it in 3D.
Why it happens
- Cachexia, anorexia nervosa and bulimia
- The hypothalamic–pituitary system: overview
- The menstrual cycle: ovary and endometrium
- The HPA axis and its circadian rhythm
- Leptin, appetite and obesity
What it is
Absence of menses caused by suppression of the pulsatile secretion of gonadotropin-releasing hormone (GnRH) by the hypothalamus, in the absence of an organic cause, triggered by low energy availability, excessive exercise and/or psychological stress.
Who gets it
One of the most common causes of secondary amenorrhoea in adolescents and young women, especially in competitive athletes, dancers, models and women with eating disorders. It is also a cause of primary amenorrhoea when it starts before menarche.
Causes
- Low energy availability: restrictive eating, weight loss or low body weight
- Excessive exercise, especially endurance and aesthetic sports
- Psychological stress, anxiety and depression
- Eating disorders (anorexia nervosa, bulimia nervosa)
- Often a combination of the above
Risk factors
- Competitive or elite sport, ballet and gymnastics
- Low body mass index or recent marked weight loss
- Perfectionism, high psychosocial stress
- Restrictive diets and vegetarian diets with insufficient energy intake
- History of eating disorder
Pathophysiology
When energy intake falls short of energy spent, or under chronic stress, cortisol rises and leptin and insulin fall. These signals reduce the frequency of GnRH pulses from the hypothalamus. With fewer pulses, the pituitary releases little LH and FSH, follicles do not mature and the ovaries produce little oestradiol. The endometrium stays thin and does not bleed. Low oestrogen removes protection from bone, reducing bone density, and also impairs vascular function. The female athlete triad links low energy availability, menstrual dysfunction and low bone density.
Classification
- Weight-loss or nutrition related
- Exercise related
- Stress related
- Mixed (most cases)
Symptoms and signs
- Absence of periods for 3 months or more (or primary amenorrhoea)
- Low or falling weight, restrictive eating or intense training
- Cold intolerance, fatigue, bradycardia
- Vaginal dryness and low libido from low oestrogen
- Stress fractures
- Infertility
Diagnosis
- Clinical
- A diagnosis of exclusion based on history of reduced intake, exercise or stress, careful weight and diet history and screening for eating disorders, after other causes have been ruled out.
- Tests
- Pregnancy test first. Low or low-normal LH and FSH with low oestradiol; normal prolactin, TSH and free T4; androgens if hyperandrogenism is suspected (PCOS). A negative progestin withdrawal test reflects low oestrogen. Electrolytes and blood count in suspected eating disorder.
- Imaging
- Bone densitometry (DXA) after about 6 months of amenorrhoea. Pituitary MRI when there are headaches, visual changes or no clear functional cause. Pelvic ultrasound shows a thin endometrium.
Differential diagnosis
- Pregnancy
- Polycystic ovary syndrome
- Hyperprolactinaemia or prolactinoma
- Thyroid disease
- Primary ovarian insufficiency (high FSH)
- Asherman syndrome or Müllerian anomaly (outflow tract cause)
Goal of treatment
Restore energy balance and normal hypothalamic function so that menses return, protect bone and heart, and address the underlying eating behaviour, training load and stress.
Treatment
- Lifestyle
- Increase energy intake, reduce training intensity and restore weight with a dietitian; this is the first-line and most effective treatment.
- Conservative
- Cognitive behavioural therapy and psychological support for stress and disordered eating; multidisciplinary care with sports medicine and mental health.
- Medical
- If menses do not return after a trial of lifestyle change, short-term transdermal oestradiol with cyclic progestin protects bone; combined oral contraceptives are not preferred because they mask recovery and protect bone poorly.
- Medical
- For women seeking pregnancy: ovulation induction with pulsatile GnRH or gonadotropins, ideally after energy balance is restored.
- Follow-up
- Follow weight, menses and bone density; calcium and vitamin D adequacy.
Complications
- Low bone mineral density, osteoporosis and stress fractures
- Infertility
- Cardiovascular dysfunction from low oestrogen
- Depression and anxiety
- Medical complications of an underlying eating disorder
Prognosis
Most women recover menses once weight, nutrition and stress are corrected, though recovery may take months. Bone loss during adolescence may not fully recover, so early treatment matters.
Prevention
- Adequate nutrition for the level of training, education of athletes and coaches about the female athlete triad, and early screening for eating disorders
Test yourself
Think of the answer, then tap the question to see it.
A 19-year-old marathon runner has had no periods for 6 months; pregnancy test negative, LH/FSH low, oestradiol low, prolactin and TSH normal. Diagnosis?
Functional hypothalamic amenorrhoea.
What is the first-line treatment?
Restoring energy balance: increase intake, reduce exercise and address stress.
Which test should follow 6 months of this amenorrhoea?
Bone densitometry (DXA), because low oestrogen causes bone loss.
What three components form the female athlete triad?
Low energy availability, menstrual dysfunction and low bone mineral density.
How do gonadotropins differ between this condition and primary ovarian insufficiency?
Low or normal in hypothalamic amenorrhoea; high in primary ovarian insufficiency.
Related conditions
- Anorexia nervosa
- Bulimia nervosa
- Osteoporosis
- Polycystic ovary syndrome
- Primary ovarian insufficiency
- Prolactinoma (hyperprolactinaemia)
- Hypothyroidism
- Asherman syndrome (intrauterine adhesions)
- Müllerian anomalies (MRKH, septate uterus, imperforate hymen)
- Female infertility
- Hypopituitarism (incl. Sheehan syndrome and pituitary apoplexy)
- Major depressive disorder
Educational information, not medical advice. For any symptom, see a health professional.
Sources: Absent menstrual periods - secondary: MedlinePlus Medical Encyclopedia (MedlinePlus (U.S. National Library of Medicine), 2024); Absent menstrual periods - primary: MedlinePlus Medical Encyclopedia (MedlinePlus (U.S. National Library of Medicine), 2024).
Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake
Representative model, for educational purposes only.
