Women's health, the Menstrual cycle part 1
Recap of progesterone: 1. where is it made? 2. what happens when progesterone is present? 3. what happens when progesterone decreases?
1. Made by corpus luteum 2. When progesterone is *present*: -Inhibits FSH and LH secretion from pituitary gland -Causes endometrium to become vascularized and increase glandular secretions 3. When progesterone *decreases*: -Opposite happens and necrosis and bleeding occur -Positive feedback to hypothalamus kicks back in again, causing rise in FSH again
Recap of estradiol: 1. What is estradiol secreted by? 2. what happens when estradiol is present?
1. Secreted by oocytes in ovary in response to FSH -The dominant follicle in each cycle is the one that produces the most estradiol 2. -Stimulates proliferation of endometrium -Inhibits FSH and LH through negative feedback on the pituitary -Triggers LH surge
1. The first day of the menstrual cycle is day number _____ of bleeding. 2. the average menses lasts _______ days 3. the average amount of blood lost during a menses is __________ ml
1. day #1 2. 3-6 days 3. 30-50 ml
what days are the luteal phase?
14-28
what is the length of a menstrual cycle?
28 days
A person is considered to have heavy menstrual bleeding when their menstrual period is typically over ______ ml
80 ml
during the endometrial sloughing process are the hormone levels high or low?
At this stage, all hormone are *low* (estrogen, progesterone, LH, FSH)
Regular menstrual cyclic changes that are considered periodic are preparation for what?
Fertilization and pregnancy
what are the 2 phases of the menstrual cycle in the ovaries?
Follicular phase and luteal phase
what is the most common reproduction disorder in women?
PCOS
what are other ovarian causes of secondary amenorrhea?
Primary ovarian insufficiency (premature ovarian failure)
What are the 2 age numbers you should remember for primary amenorrhea?
*13 and 15*
Since the hormones (estrogen and progesterone are low during the endometrial sloughing, what is released from the hypothalamus?
*GnRH* GnRH stimulates pituitary to start releasing FSH -FSH levels start to rise -FSH stimulates maturation of oocytes (immature ova) -At birth, the ovary contains many primordial follicles under the surface of the ovarian capsule -Each follicle contains an oocyte
what are the features of PCOS?
*androgen excess (acne, hirsutism), ovulatory dysfunction, polycystic ovaries* -causes abnormal follicular growth and secretion of androgens
This is a condition that has the absence of uterus, cervix, and or vagina and causes primary amenorrhea:
*muellerian agenesis*
If a 12 or 13 year old pt presents with cyclic pelvic pain with primary amenorrhea what differential diagnosis should you keep in mind?
*obstructed mullerian outflow tract*
what is the *most common cause of secondary amenorrhea?*
*pregnancy*
what is released from the endometrial cells during the sloughing process?
*prostaglandins*- cause. uterine contraction (cramps)
What is the definition of primary amenorrhea?
-*absence of menses by age 15/16*
Luteal phase:
-Corpus luteum secretes progesterone -Progesterone causes endometrium to become vascularized and increase glandular secretions in preparation for a possible implantation -Corpus luteum continues to secrete progesterone for about 11 days without the presence of hCG -hCG = human chorionic gonadotropin (produced by an embryo) -If fertilization occurs, corpus luteum is maintained by the hCG from the embryo (continuing progesterone production) -Progesterone inhibits FSH and LH secretion from pituitary -Prevents the body from developing more oocytes and triggering another ovulation before implantation has had a chance to occur (CL by itself) or when implantation has occurred (CL maintained by hCG) -If fertilization does NOT occur, the corpus luteum breaks down and regresses (because hCG not present) -When the corpus luteum regresses, progesterone decreases (support for the endometrium is withdrawn) -Estradiol levels fall (was produced by oocytes under stimulation of FSH) -With the fall of progesterone, the HPO axis is released from inhibition -Cycle starts again with GnRH from hypothalamus stimulating pituitary to start releasing FSH again -Decreasing progesterone levels prompt endometrial sloughing once again -Vasculature of endometrium necroses (causing bleeding) -Follicular phase begins again
Information about ovulation:
-Estradiol peaks 1 day before ovulation, triggering the LH surge -The previously negative feedback of estradiol on LH switches to a positive feedback, causing the LH surge -Many follicles are actually stimulated by FSH, but one follicle in one ovary secretes more estradiol than others, becoming the dominant follicle -The dominant follicle becomes dominant by day 6 -Around the 14th day of the cycle, the LH surge triggers the distended dominant follicle to rupture, and the oocyte is released into the abdominal cavity -This event is ovulation -Oocyte is picked up by the fallopian tubes and transported to the uterus -The structure remaining after oocyte is gone is the corpus luteum -Corpus luteum = degenerating dominant follicle -If fertilization does NOT occur, the oocyte degenerates
what are hypothalamic causes that cause primary/secondary amenorrhea?
-Kallman Syndrome: congenital absence of GnRH -Compression of pituitary stalk by tumor -Decreased GnRH release -Stress -Anorexia nervosa -Weight loss -Extreme exercise -Hyperprolactinemia (prolactin inhibits GnRH)
what is the definition of secondary amenorrhea?
-MUST have had *at least one menses* -absence of menses for *3 months* if previous cycles *were normal* -absence of menses for *6 months* if cycles were *irregular*
primary amenorrhea: what happens at age 15 that should prompt you to evaluate for primary amenorrhea? what happens at age 13 that should prompt you to evaluate for primary amenorrhea?
-No menses *age 15 w/normal growth and secondary sexual characteristics* Earlier onset of menarche; consider evaluating a girl for primary amenorrhea if her menses have not occurred by age 15 years -At age *13 years, if w/o menses and w/o secondary sexual characteristics*, evaluation for primary amenorrhea should be begun.
what is sheehan syndrome? what are signs and symptoms of Sheehan syndrome?
-Occurs with severe blood loss and hypotension *during delivery of baby* -Hypotension causes damage (secondary to *oxygen deprovation) to the pituitary* -Signs and symptoms of Sheehan's syndrome occur because of having too little of the hormones the pituitary gland controls: thyroid, adrenal, breast milk production and menstrual function hormones.
More information on the follicular phase:
-Oocytes secrete estradiol in response to FSH -Estradiol then inhibits FSH and LH through negative feedback on the pituitary -Oocytes also secrete inhibin, which also inhibits FSH secretion -Estradiol positively stimulates proliferation of endometrium -Under the influence of estrogen from developing follicles, the endometrium regenerates and increases rapidly in thickness during days 5-16
Other causes or primary amenorrhea:
-Transverse vaginal septum or imperforate hymen (5%) -Chromosomal abnormalities causing gonadal (ovarian) dysgenesis (failure of the gonads to develop and produce sex hormones) - *50%* -hypothalamic hypogonadism including function hypothalamic amenorrhea- *20%* -pituitary disease- *5%* -Combination of disorders; androgen insensitivity due to mutations in the androgen receptor, congenital adrenal hyperplasia, and polycystic ovary syndrome -*5%*
Primary amenorrhea is usually a result of what?
-a genetic or anatomical abnormality.
what are mechanical causes of primary amenorrhea?
-imperforate hymen -cervical stenosis -abnormal development (no uterus) -transverse vaginal septum -asherman syndrome -intrauterine adhesions -uterine scarring after dilation and curettage (D&C) -adhesions can cause a mechanical obstruction of uterus
when does menopause occur in primary ovarian insufficiency (premature ovarian failure)?
-menopause before age 40
Review: causes of secondary amenorrhea:
-pregnancy -obesity -excessive or prolonged periods of exercise -ultra-low body fat -anxiety and stress -sudden weight loss -brain tumors (specifically of the pituitary) -cancer treatment -schizophrenia or phycosis medications -hyperthyroidism -PCOS -scar tissue for D&C
what does the follicular phase represent?
-represents sloughing of the epithelium from the preceding cycle
what is unique about kallmann syndrome and its relation to smell?
-the sense of smell is either diminished or completely absent
True or false: PCOS causes 20% of cases of amenorrhea and 50% of cases of oligomenorrhea?
True
True or false: the length of the luteal phase is *constant*?
True -length is about 14 days
what are causes of primary ovarian insufficiency (premature ovarian failure)?
Turner syndrome (XO karyotype): ovarian dysgenesis; more commonly etiology undetermined.
What day is ovulation?
day 14
Follicular phase is day __________ of the menstrual cycle
days 1-14
what does mittelschmerz mean?
mid-cycle
what are pituitary disorders that can causer secondary amenorrhea?
pituitary infarction, prolactinoma, Iron (hemosiderin deposition in pituitary)
what happens to progesterone when fertilization does *NOT* occur?
progesterone levels *drop* after the corpus lute has regressed
how does prolactin affect GnRH?
prolactin inhibits GnRH
what is another name for follicular phase?
proliferative phase and pre-ovulatory phase.
what does the luteal phase represent?
represents preparation of the uterus for implantation of the fertilized ovum
what is another name for luteal phase?
secretory phase
Why does sloughing occur?
sloughing occurs because fertilization did *NOT* occur in the preceding cycle
What is another name for endometrial sloughing (bleeding)?
start of the menses
True or false: in the follicular phase the length of the menstrual cycle is variable in length and is due to variability of follicular phase?
true
How does iron deposition affect the pituitary?
with iron deposition it impairs the pituitary's function and causes decreased FSH and LH.