Lyrics · 完整歌詞
The assessment of amenorrhoea in a person of reproductive age begins by
excluding pregnancy before investigating other causes.
Secondary amenorrhoea is defined as three months without menses in a woman who previously
cycled.
Primary amenorrhoea means no menarche by fifteen,
or no secondary sexual characteristics by thirteen.
Once pregnancy is excluded, TSH and prolactin measurements help identify common,
potentially treatable endocrine causes.
FSH then separates ovarian failure, where it is high,
from hypothalamic or pituitary causes, where it is low.
A progestogen challenge that produces a withdrawal bleed proves the presence of oestrogen
and an open outflow tract.
The cycle itself runs on a single act of positive feedback.
Low oestradiol in the early follicular phase suppresses FSH,
whereas sustained high oestradiol before ovulation triggers the LH surge.
Ovulation follows the surge by roughly ten to twelve hours,
and the corpus luteum survives a fixed fourteen days
unless hCG rescues it.
Production is shared between two cells:
LH drives theca cells to make androgens,
and FSH drives granulosa cells to aromatise them into oestradiol.
GnRH must arrive in pulses; continuous agonist exposure downregulates the axis,
which is precisely how fibroids and precocious puberty are treated.
The assessment of amenorrhoea in a person of reproductive age begins by
excluding pregnancy before investigating other causes.
Polycystic ovary syndrome is a chain that starts with insulin.
Hyperinsulinaemia stimulates theca androgen synthesis and suppresses hepatic SHBG,
so free androgen rises, follicles arrest and ovulation fails.
The Rotterdam criteria require two of three features: oligo-anovulation,
clinical or biochemical hyperandrogenism, and polycystic morphology,
now twenty or more follicles per ovary
or a volume of ten millilitres.
Obesity and insulin resistance, however common, are not criteria.
Chronic anovulation leaves the endometrium under unopposed oestrogen,
and hyperplasia and carcinoma follow over years.
Management follows what the woman wants.
For an overweight woman not yet seeking pregnancy,
weight loss of five to ten per cent is first-line
and often restores ovulation.
Cyclic progestogen at least every three months, or the combined pill,
protects the endometrium.
When conception is desired, letrozole now outperforms clomiphene for live birth,
with metformin as a second-line adjunct.
Hirsutism responds to the combined pill, with spironolactone added when needed.
Primary amenorrhoea is read along one axis: breasts, then hair, then uterus.
Breasts without axillary or pubic hair mark complete androgen insensitivity, 46,XY,
where testicular anti-Müllerian hormone has removed the uterus.
Breasts and hair without a uterus mark Müllerian agenesis, 46,XX,
which demands renal imaging.
Without breasts,
a high FSH indicates Turner syndrome
and a low FSH indicates Kallmann syndrome with anosmia.
Outflow obstruction such as an imperforate hymen must never be treated with
progestogen to induce a bleed.
The assessment of amenorrhoea in a person of reproductive age begins by
excluding pregnancy before investigating other causes.