Synopsis
Approach absent menstruation from pregnancy and anatomy through ovarian and hypothalamic-pituitary physiology, identify urgent endocrine disease, and protect bone, endometrium and fertility while treating the cause.
- Exclude pregnancy first in every person with pregnancy potential, regardless of stated infertility, contraception, sexual orientation or cycle irregularity.
- Primary amenorrhoea concerns menstruation that has not begun by the age or pubertal stage in current guidance; secondary amenorrhoea is loss of established bleeding for a clinically significant interval.
- The presence of breasts, uterus, cervix and androgen signs directs primary amenorrhoea assessment before a long laboratory list is ordered.
Key red flags
Galactorrhoea, low libido, headache or visual change with suppressed gonadotrophins suggests prolactin excess, although galactorrhoea may be absent and medicine causes are common.
Investigation priorities
Exclude pregnancy before endocrine testing, imaging choices or hormone treatment.
Management branches
Previously established menstruation has stopped beyond the current clinical threshold.
- Test for pregnancy and assess pain, bleeding, haemodynamic symptoms, contraception, lactation, medicines, weight or intake change, exercise, stress and chronic illness.
- Examine blood pressure, thyroid, galactorrhoea, androgen and Cushing features and signs of energy deficiency, using trauma-informed discussion of eating and pregnancy possibility.
Key medicines
CabergolineStart and titrate using the endocrine or fertility protocol to prolactin response and clinical goal.
LevothyroxineUse the licensed once-daily regimen titrated to thyroid tests and pregnancy-specific targets when indicated.