Menstruation and Menstrual disorders Flashcards
What checking for a normal menstrual cycle…
- When does ovulation occur?
- When is the progesterone peak?
- How long does the luteal (2nd half; 1st half is follicular) phase last?
- ovulation = day 14
- with peak in LH and FSH & oestrogen drop
- progesterone peak = day 21 in 28d cycle
- when progesterone decreases –> menses @ end of menstrual cycle & signifying the START
- luteal phase (after ovulation) = always 14 days
Menstruation:
follicular (variable) –> ovulation –> luteal
What type of feedback loop do progesterone, testosteronoe and oestrogen have?
- Progesterone & testosterone always -ve feedback
- Oestrogen can also cause +ve feedback
What is the name for the variable first half of the menstrual cycle and the fixed 14d part 2 of the menstural cycle?
variable = 1st part till ovulation = follicular
fixed @14 days after ovulation until menstruation = luteal phase
Just after menstruation, in the follicular phase which are the first 2 hormones to start to rise?
What do these hormones do?
- LH and FSH start to rise
- (after GnRH stimulates gonadotroph cells of the pituitary to release/synthesise them;
- vs posterior pituitary doesnt make the 2 hormones it has it just stores and secretes them from the hypothalamus)
- FSH –> stimulates granulosa cells –> produce OESTROGEN (from the androgens made by LH)
- LH –> Theca cells –> androgens
FSH –> stimulates granulosa cells –> produce OESTROGEN (from the androgens made by LH via theca cells)
What happens to oestrogen throughout the follicular phase?
Which hormone surge causes ovulation
Unopposed oestrogen
- -ve feedback on HPG axis as we are mono-ovular (also role of inhibin)
- Then when lots of oestrogen—>
- switch to +ve feedback
- –> changes amplitude & frequency of hypothalamus pulses (e.g.? higher peaks and more often)
- –> pituitary LH surge
- Pituitary LH surge –> 36hrs later = ovulation!
in the luteal phase of the menstrual cycle how does the growth of the antral follicles occur?
- Growth of antral follicles occurs in response to inter-cycle rise in FSH –> up to ovulation
- then FSH falls… due to -ve feedback
- @ ovulation time the DOMINANT follicle is selected because although FSH is falling the dominant follicle acquired LH receptors on the granulosa cells
- there is an LH surge -> ovulation of the dominant follicle (due to newly acquired LH receptors)
NB: oocyte completes 1st meiotic division but doesnt divide
due to increasing E2 receptors the uterine tubes undergo tube differentiation. Due to progesterone suppressing E2 receptors there is tube un-differentiation in the uterine tubes.
Therefore, which phases of the menstrual cycle does tube differentation vs tube undifferentiation occur?
What changes happen in both?
- Tube Differentiation (↑E2 receptors) occurs in FOLLICULAR phase (f for first)
- -differentiation
- -secretion
- -cilia growth
- -peristaltic contraction of muscle (pushes egg along for ovulation)
- Tube Un-differentiation (P supresses E2r’s) occurs in LUTEAL phase (L for later); basically everything from tube differentiation undoes
- -un-differentiation
- -secretions halt
- -cells decrease in height
in terms of the endometrium throughout the menstural cycle there is a secretory and a proliferative phase. Which one corresponds with which part of the ovarian cycle. e.g. the follicular and luteal phases?
Proliferative = occurs in follicular phase - makes lining all squashy for new egg
- proliferation of stomal layer
- ciliated surface
- glands expand & coil
- neo-angiogenesis of spiral artries
Secretory phase part 1
- differentiation of new layer
- oedema (inflammatory infiltrater) & ↑vascular permeability & coiling of spiral arteries
- maturation of glands → glycoproteins, lipids GF, cytokines, adhesion molecules
Part 2 - pro-constrictor PGs dominate
- Constriction of spiral arteries (24hrs preceding menstruation) –> ischaemia
- –> vessels themselves become ischaemic & fall apart –> start bleeding from very lowest part of artery that is still patent
In terms of the cervix what changes occur in the 1st half of the menstrual cycle vs 2nd half?
Cervix 1st half MC:
- Vascular changes & oedema → mucus more water to allow passage of sperm
- Mid-cycle E2 changes: glycoproteins become aligned & form microscopic channels sperm swim up
Cervix 2nd half MC:
- More viscous mucous (less water content)
- Glycoproteins now form mesh, acting as barrier
- (mechanism of oral contraceptives, ?so from progesterone then?)
The second half of the menstural cycle, the luteal phase is fixed at 14 days.
once the LH surge has occured and released the dominant follicle for ovulation, what happens to the hormone balance in the body if the woman IS PREGNANT?
- Just after ovulation
- Follicle –> to corpus luteum
- (keeps uterine lining cushy via progesterone for the growing egg)
- –> makes progesterone & oestrogen
- –> p –> -ve feedback on LH & FSH
- Follicle –> to corpus luteum
- IF PREGO
- CL saved by bHCG binding to LH receptors
- –> saves for 1st 7 weeks of pregnancy, after that the placenta takes over
NB: bHCG is a type of gnrh hormone along with LH and FSH then
The second half of the menstural cycle, the luteal phase is fixed at 14 days.
once the LH surge has occured and released the dominant follicle for ovulation, what happens to the hormone balance in the body if the woman IS NOT PREGNANT?
Just after ovulation
- Follicle to corpus luteum (keeps uterine lining cushy via progesterone for the growing egg)
- –> makers progesterone & oestrogen
- –> -ve feedback on LH & FSH
NOT PREGO
- CL undergoes programmed cell death after 14d –> corpus albicans
- Oestrogen & progesterone not made, serum levels drop right down
–> BLEED + back to day 1
(FSH –> follicles & oest and LH on theca w/androgens)
What happens in the luteal phase of the menstural cycle (non pregnancy)?
- Corpus luteum formed from empty follicle (made of cholesterol)
- Corpus albicans is formed from programmed cell death of CL (@14d) –> doesn’t produce oestrogen or steroids
What is the process called of how the dominant follicle forms a corpus luteum just after ovulation?
lutenisation
- the follicle cells collapse –> corpus luteum
- fertilise oocyte prevents death of CL from LH and hCG receptors
- otherwise if not fertilised = 14 day lifespan of CL
- the vasculature breaksdown and CL shrinks -> albicans
- the progesterone released from CL –> supports oocyte in journey, controls cells of tubes & alters secretions of cervix and prepares endometrium
- (secretory phase = new layer differentiation, oedema and vasc perm, on the primed layer by oestrogen in follicular/proliferative phase)
- secretion of oestrogen: for endometrium in luteal phase too (Cl gives P and O)
How are oocytes preapred for ovulation?
- after the domionant follicle released in response to LH surge - ovulation –> oocyte completes 1st meiotic division (but doesnt divide)
- –> this arrested 1st meiotic division keeps all DNA and size as long as possible
- 1/2 the chromosomes are put into 1st polar body egg (NOT split into another secondary oocyte)
- oocyte begins and arrests in 2nd meiotic division (until fertilisation)
What is the ovulation cascade?
The travelling of the oocyte down the fallopian tube by peristalsis & action of cilia
- increase blood flow & vascular permeability to follicle causes increased intra follicular pressure
- stigma / apex appearance on ovary wall & local protease action causes HOLE
- oocyte and cumulus cells released (from cortex) & collected by fimbria of uterine tubes
- (to travel down tube by peristalsis etc)
What disorders of menstrutation exist?
- amenorrhoea/oligomenorrhoea
- inter-menstrual bleeding
- post-coital bleeding
- menorrhagia
What is the definition of amenorrhoea?
no periods for >6 months
-
1o:
-
never bled by 16 years - 95% will have
- (doesnt mean theres a problem but much more likely to be)
- or no bleeding + no secondary characteristics by 14 yrs
-
never bled by 16 years - 95% will have
-
2o:
- cessation of periods for 6 months (4 P’S as causes)
- Pregnancy
- Prolactinoma (high pro affects P and O in menstural cycle)
- PCOS
- Premature ovarian insufficiency
- cessation of periods for 6 months (4 P’S as causes)
What is the #1 rule with amenorrhoea?
ALL WOMEN ARE PREGNANT UNTIL PROVEN OTHERWISE
What are the hypothalamic causes of amenorrhoea?
hypothalamus –> GnRH –> anterior pituitary –> FSH & LH
e.g. hypogonadotrophic hypogonadism –> there is no LH or FSH
- Non-functional hypothalamic hypogonadism
- Tumour
- Kallman syndrome - X-linked recessive disorder characterised by failure of migration of GnRH cells.
- Functional hypothalamic hypogonadism
- Anorexia
- (lack of body fat - Leptin initiates menstruation,
- BMI<17
- they stop & can take up to 2yrs for )
- Excessive exercise (lack of fat) –> loss of GnRH pulses
- Iatrogenic e.g. Radiotherapy, surgery
- Pseudocyesis (phantom pregnancy)
- Anorexia
What are the pituitary causes of amenorrhoea?
e.g. hypogonadotrophic hypogonadism –> there is no LH or FSH
hypothalamus –> GnRH –> anterior pituitary –> FSH & LH
- Raised prolactin
- prolactinoma (inc. pro affects P &O),
- anti-psychotics,
- renal failure?? (CKD = increased PRL retention & production)
- Breast feeding
- (the raised prolactin is the contraceptive method behind breast feeding amenorrhoea)
- Pituitary adenoma
- (macroadenoma, microadenoma)
- Pituitary failure
- SOL e.g. acromegaly, Cushing’s syndrome
- Sheehan syndrome - massive PPH causes hypotension & injury to lactotrophs in pituitary –> hypopituitarism e.g. amenorrhoea and no milk produced
- Iatrogenic e.g. radiation, surgery
- Autoimmune destruction of pituitary
-
Post-contraception amenorrhoea -
- prolonged use of contraceptives can cause LT downregulation of pituitary gland & irregular/absent periods or lack of ovulation which persists;
- most commonly seen with Depo-Provera (can take 18months for menses to resume)
A lady has just given birth, it was a traumatic birth with massive PPH causing severe hypotension. In the end both the baby and herself recovered however, she has come to clinic due to an inability to produce breast milk. She has not gotten her periods back.
How would you investigate this syndrome?
Sheehan syndrome - massive PPH causes hypotension & injury to lactotrophs in pituitary –> hypopituitarism). Symptoms –> lack of post-partum milk production, amenorrhoea following delivery with hx massive PPH
Ix = bloods =>
- PRL,
- gonadotrophin stinulation tests (hypopituitarism)
The most common cause of amenorrhoea is due to ovarian causes.
What are the differentials for ovarian causes of amenorrhoea?
- PCOS
- (hyper-oestrogenic, anovulatory)
- (high testosterone, low Sex Hormone Binding Globulin)
- Premature ovarian failure
- (hyper-gonadotrophic) - <40yrs - main reason we check - cause by chemotherapy or bad luck…
- Turners 45 XO
- amenorrhoea,
- failure to develop secondary sexual characteristics and
- almost universal infertility
- short stature,
- webbed neck and aortic coarctation.
- short stature,
- Gonadal dysgenesis
A 16 year old girl presents with amenorrhoea, lack of pubic hair and breast buds. She is short of stature with webbed neck.
What is the likely cause and what other malformation would be likely found?
Turners 45 XO
- aortic coarctation, almost universal infertility, (streak ovaries)
What endometrial problems can cause amenorrhoea?
inter-uterine adhesions
(Asherman syndrome)
(also consider TB)
on hyteroscopy a patient has inter-uterine adhesions…
what is the name of this syndrome?
what else would need considering?
Asherman syndrome
- also consider TB
Outflow disorders of the vagina and cervix can cause amenorrhoea - by obstruction.
What can cause cervical/outflow obstruction?
- Mullerian agenesis
-
MKHR syndrome (Mayer-Rokitansky-Kuster-Hauser syndrome)
- – agenesis of the Mullerian-duct system in varying degrees;
- congenital absence of the uterus and upper two thirds of the vagina and therefore a cause of primary amenorrhoea.
- – agenesis of the Mullerian-duct system in varying degrees;
-
MKHR syndrome (Mayer-Rokitansky-Kuster-Hauser syndrome)
- Transverse vaginal septum - septum between upper & lower embryological origins of vagina
- Imperforate hymen
- Cervical stenosis
- Asherman’s syndrome (inter-uterine adhesions)
What endocrine causes of amenorrhoea are there?
- Androgen insensitivity
- (genetically male, phenotypically female bc -
- -> gonad selection is male but receptors insensitive so female outside, male inside)
- Adrenal
- e.g. congenital adrenal hyperplasia - CAH (too much androgens > mineral/glucocorticoids)
- & deficiency of 21 hydroxylase enzyme (the most common cause of CAH)
- Obesity (excess oestrogen –> -ve feedback
- Cushing’s
- Clinical hypo/hyperthyroidism