Puberty and amenorrhoea

Puberty sequence and timing

• Puberty begins with pulsatile GnRH, then LH/FSH, ovarian estrogen and secondary sexual development.
• Typical order: thelarche, pubarche, peak height velocity, then menarche 2-3 years after thelarche.
• Evaluate no breast development by 13 years, no menses by 15 years, or no menses within 5 years after early thelarche.

Primary amenorrhoea map

• Exclude pregnancy when biologically possible.
• Ask breasts present, uterus present, then read FSH and estradiol.
• Absent uterus with breasts: MRKH has normal hair and 46,XX; CAIS has sparse hair and 46,XY.
• Uterus present with cyclic pain suggests outflow obstruction.

Secondary amenorrhoea map

• Investigate more than 3 months absent after regular cycles or more than 6 months after irregular cycles.
• First test is beta-hCG, then TSH, prolactin, FSH and estradiol.
• High FSH means ovarian failure; low/normal FSH with low estradiol points central.
• Postpartum haemorrhage plus lactation failure suggests Sheehan syndrome.

Must-not-miss safety

• Precocious or rapidly progressive puberty with neurological symptoms needs urgent endocrine review.
• Cyclic pelvic pain with no menses can be obstructed outflow.
• Amenorrhoea of reproductive age can be pregnancy, including ectopic pregnancy.