Normal menstrual cycle Flashcards
average duration of normal adult reproductive cycle
28 days
what are the three distinct ovarian phases
- follicular phase: onset of menses and ends at LH surge
- ovulation: occurs within 30-36 hours of LH surge
- luteal phase: begins on day of LH surge and ends with onset of menses
how long do the follicular and luteal phases last in a normal menstruating woman?
follicular phase - 14 days
luteal phase - 14 days
in irregular cycles, how are the follicular and luteal phases affected?
duration of luteal phase remains fairly constant; duration of follicular phase can vary
what is the normal volume of menstrual blood volume?
30 mL (1 ounce)
what is an abnormal amount of menstrual blood volume?
greater than 80 mL
what organ serves as the pulse generator of the reproductive cycle?
hypothalamus
what does the corpus luteum secrete upon ovulation?
progesterone
where are the primordial germ cells? where do they go from there, and what do they do?
endoderm of yolk sac
migrate to genital ridge by 5-6 weeks gestation, then wildly multiply
what is the first visible sign of follicle recruitment?
an increase in size and change in granulosa cell shape
follicular phase - preantal - what happens?
- oocyte enlarges and is surrounded by single layer of granulosa cells and a membrane - zona pellucida
- FSH binds to FSH receptors on granulosa cells
what does the preantral follicle do in response to FSH?
aromatize androgens to estrogens
which cells produce estrogen? which receptors do they have?
granulosa cells
FSH
which cells produce androgens? which receptors do they have?
theca cells
LH
what are the criteria for folllicle progression in terms of hormone levels?
- elevated FSH
- low LH
the success of a follicle depends on what factors?
ability to convert an androgen microenvironment to an estrogen one
ovarian steroidogenesis is always dependent upon which hormone?
LH
events of follicular phase - antral
what must the granulosa cell acquire in order to respond to ovulation?
- increase in follicular fluid
- granulosa cells must acquire LH receptors to respond to ovulation
which hormone rises during the antral part of the follicular phase? what is the purpose of this?
LH
stimulates androgen production in theca cells
what occurs during the preovulatory follicle phase?
- granulosa cells enlarge and acquire lipids
- oocyte resumes meiosis (has been arrested in prophase of meiosis I)
- LH promotes luteinization of granulosa which results in progesterone production
what is the time frame from LH surge to menses?
14 days, consistently
what hormone prevents luteal regression? what is its role?
HCG
maintains steroidogenesis of corpus luteum until 9-10th week of gestation
what are the three endometrial phases in an ovulatory cycle?
- menstrual endometrium and proliferative phase
- ovulation
- secretory phase
what is responsible for cessation of menstruation?
rising estrogen levels in early follicular phase - induce endometrial healing
loss of estrogen and progesterone in the absence of fertilization / implantation initiates what 3 endometrial events?
- vasomotor reactions
- tissue loss
- menstruation
70% of blood loss during menstruation occurs when?
first 2 days
definition: menorrhagia
prolonged (over 7d) or excesive (over 80 mL) uterine bleeding at regular intervals
hypomenorrhea
cycle length of 2 days or less or also can be a reduction in flow
metorrhagia
bleeding at irregular but frequent intervals or variable amount
menometorrhagia
frequent bleeding that is excessive and irregular in amount and duration
what is the most common cause of amenorrhea?
pregnancy
what are causes of HP amenorrhea?
- functional
- drug induced
- neoplastic
- psychogenic
- other
what is the definitive way to diagnose HP dysfunction for amenorrhea?
measure FSH, LH, and prolactin serum levels
FSH and LH will be low
prolactin may be normal
what is asherman syndrome?
- scarring of uterine cavity
- most frequent anatomic cause of secondary amenorrhea
how is amenorrhea diagnosed and treated? how is it performed and what are the results?
progesterone challenge test - assesses if pt has adequate estrogen, competent endometrium, and an adequate genital outflow tract
- induces a progesterone withdrawal bleed within one week of completing 10-14 day course of oral progesterone
- if bleeding occurs - pt is anovulatory
- if no bleeding - hypoestrogenic or anatomic
how is hyperprolactinemia treated?
bromocriptine or cabergoline
what is done if a patient with amenorrhea desires to get pregnant?
ovulation can be induced with clomiphene citrate, human menopausal gonadotropins, pulsatile GnRH, or aromatase inhibitors
what describes abnormal uterine bleeding - luteal phase defect? what happens to the menstrual cycle?
- ovulation occurs bu the corpus luteum doesnt secrete adequate quantities of progesterone to support the endometrium and is not adequate to support a pregnancy if one occurs
- menstrual cycle is shortened with menstruation occurring earlier than expected
how can abnormal uterine bleeding lead to endometrial cancer?
chronic unopposed estrogen stimulation of the endometrium which can lead to increased proliferation followed by hyperplasia and ultimately endometrial cancer
what is necessary to diagnose endometrial cancer?
biopsy
what is the goal of treatment for AUB? what drugs can be used?
ensure regular shedding of endometrium
- progestin 10-14d: mimics the physiologic withdrawal of progesterone
- combination oral contraception: suppresses the endometrium and also establishes a regular withdrawal cycle
what is done for acute heavy abnormal bleeding? if that fails?
- high dose estrogen and/or progesterone for acute management
- followed by preventative management with itnermittent progestin treatment or oral contraceptives
if not responsive to medical management - surgical treatment with D&C (dilation and curretage), endometrial ablation, hysterectomy
what is dilation and curretage? when is it used?
- biopsy and exploration
- used for older patients who are at higher risk of having endometrial hyperplasia
what does endometrial ablation do? what is a contraindication?
changes architecture by ablating / cauterizing vessels
contraindicated in women who wish to maintain reproductive status
