Physiology - Menstrual Cycle Flashcards
what does GnRH stimulate?
release of FSH and LH from the anterior pituitary
what effect do FSH and LH have on follicles?
FSH initiates follicular growth
LH stimulates further development
what effect do FSH and LH have on the ovaries?
stimulate the follicles to secrete oestrogen
what secretes progesterone?
the corpus luteum
what effect to progesterone and oestrogen have on the endometrium?
prepare and maintain it for implantation
how long is a normal menstrual cycle?
24-38 days
no more than 9 days variation
how long should bleeding last in a normal menstrual cycle?
no more than eight days
when does the menstrual phase occur?
roughly the first five days of the cycle
what happens in the ovaries during the menstrual phase?
primary follicles develop into secondary follicles under the influence of FSH
what happens in the uterus during the menstrual phase?
fall in oestrogen + progesterone causes release of prostaglandins, causing arteriolar construction
cells die off and stratum functionalis sheds
what time period has the main impact on the length of a menstrual cycle?
the time between menstruation and ovulation
what happens in the ovaries during the preovulatory phase?
secrete oestrogen
one follicle outgrows the rest and becomes the Graafian follicle
what happens in the uterus during the preovulatory phase?
new stratum functionalis produced
endometrial thickness doubles
when does ovulation occur in a 28 day cycle?
day 14
what happens in the ovaries during the ovulatory phase?
oestrogen stimulates GnRH, which causes an LH surge
this causes expulsion of the oocyte from the Graafian follicle
how long does the postovulatory phase last?
14 days - constant
what happens in the ovary during the postovulatory phase?
follicle becomes the corpus luteum under the influence of LH
what hormones does the corpus luteum secrete?
progesterone
oestrogen
relaxin
inhibit
what do the endometrial glands secrete during the postovulatory phase?
glycogen
what are pre-menstrual disorders (PMD)?
when premenstrual symptoms have an impact on daily living
for a diagnosis of PMD, when must symptoms occur?
must be cyclical
occur in the post-ovulatory or luteal phase
what are some physical symptoms of PMD?
breast tenderness bloating headache skin problems weight gain
what are some psychological symptoms of PMD?
mood swings
anger
depression
suicidal ideation
what are some behavioural symptoms of PMD?
sleep disturbance appetite changes restlessness poor concentration confusion
how is PMD diagnosed?
symptom diary filled out for a minimum of two cycles
what is the principle of management of PMD?
ovulation suppression
what is the first line management for PMD?
COC
needs to contain drospirenone
what is a second line option for management of PMD?
GnRH agonists
for a maximum of six month
what are possible side effects of GnRH agonists?
vasomotor side effects such as hot flushes and osteoporosis
what is the final option for management of PMD?
bilateral oophorectomy and hysterectomy
what is heavy menstrual bleeding?
blood loss that impacts with life
what needs to be excluded when someone presets with heavy menstrual bleeding?
pregnancy
what investigations are done for heavy menstrual bleeding?
FBC smear swabs for infection USS coagulation screen if indicated
what is the first line management of heavy menstrual bleeding?
mirena coil
how does the mirena coil help heavy menstrual bleeding?
slowly releases localised progesterone and prevents proliferation of the endometrium
what are the two second line options for heavy menstrual bleeding?
tranexamic acid
COC
what type of drug is tranexamic acid?
anti fibrinolytic
how does the COC help heavy menstrual bleeding?
suppresses ovulation and endometrial proliferation
also regulates cycles
what are the third line options for heavy menstrual bleeding?
norethisterone
DMPA injections
what is the last line management for heavy menstrual bleeding?
surgical management or referral to secondary care
what are some possible causes of heavy menstrual bleeding?
fibroids polyps adenomyosis coagulopathy malignancy
what are fibroids?
benign smooth muscle tumours of the uterus
