Clinical: Menstruation and ART Flashcards
Define the follicular phase
Begins with the onset of menses and ends on the day of the luteinizing hormone (LH) surge
Hormone levels in late luteal phase
Withdrawal of estrogen and progesterone
Phase in which the ovary is least hormonally active
Early follicular phase (low serum estradiol and progesterone)
GnRH and FSH levels during the early follicular phase
Release from negative feedback effects of estrogen and progesterone = increased GnRH pulse frequency –> 30% increase in serum [FSH]
Number of primordial follicles stimulated by FSH release from pituitary during the follicular phase
5 - 15
When is a single dominant follicle selected?
By late follicular phase
Describe the 2-cell process by which the developing dominant follicle produces estrogen
- Theca interna cells produce androstenedione in response to LH stimulation
- Granulosa cells conert androstenedione –> estradiol when stimulated by FSH
Effects of estrogen on the uterine lining during the follicular phase
Thicken/proliferate
GnRH and LH levels during the follicular phase
GnRH pulse frequency increases –> rise in LH
Effect of raised LH levels during the follicular phase
Stimulation of androgen synthesis –> androgens converted to estrogens
Peak of serum estradiol concentrations
Approx 1 day before ovulation
Midcycle LH levels (~day 14)
LH spike in response to estrogen surge
Why does ovulation occur?
Increase in LH level causes the follicle to rupture and release mature ovum
Describe the effect of rising estradiol levels at the end of the follicular phase on LH concentration
10-fold increase (positive feedback switch from negative feedback; poorly-understood phenomenon)
When does the oocyte in the dominant follicle complete the 1st meiotic division
In response to the LH surge
When is the oocyte released from follicle at ovarian surface?
~36 hours after LH surge
Even before the oocyte is released, what do the granulosa
When does the luteal phase begin?
After ovulation
What does the remnants of the follicle become after ovulation
Corpus luteum
Time it takes for the ovum to travel down the tube to the uterus
3 -4 days
When must fertilization occur and what is the consequence of it not occuring?
Must occur within 24 hours of ovulation or ovum degenerates
What forms the corpus luteum cyst and when
Granulosa and theca interna cells lining the wall of the follicle after ovulation
Function of corpus luteum
Synthesize estrogen and large amounts of progesterone
Effect of progesterone on endometrium
Stimulate endometrium to become more glandular/secretory in preparation for implantation of fertilized ovum
Substance synthesized by trophoblast if fertilization occurs
Human chorionic gonadotropin (hcg)
Function of HCG
Maintain the corpus luteum so it may continue producing estrogen and progesterone to support the endometrium
When is the placenta developed and what function does it take over?
8-10 weeks gestation
Takes over production of estrogen and progesterone
8 events occuring in the luteal phase if fertilization does not occur
- Corpus luteum is not maintained by HCG
- Corpus luteum degenerates after ~14 days
- Estrogen and progesterone levels fall
- Increased prostaglandins and leucocytes in endometrium
- Constriction of spiral arteries
- Desquamation and ischemia of endometrium
- Arteriolar relaxation, bleeding and tissue breakdown
- FSH levels slowly rise again in absence of negative feedback
2 types of dysfunctional uterine bleeding (DUB)
Anovulatory
Ovulatory
4 types of organic disease linked to abnorma uterine bleeding
- Systemic
- Reproductive disease
- Pregnancy-related
- Iatrogenic
6 common terminologies for abnormal uterine bleeding
- Menorrhagia
- Metrorrhagia
- Menometorrhagia
- Hypermenorrhea
- Polymenorrhea
- Oligomenorrhea
Bleeding cycle of menorrhagia
Regular cycles, prolonged duration, excessive flow
Bleeding pattern of metrorrhagia
Irregular cycles
Bleeding pattern of menometorrhagia
Irregular, prolonged, excessive
Bleeding pattern of hypermenorrhea
Regular, normal duration, excessive flow
Bleeding pattern of polymenorrhea
Frequent cycles
Bleeding pattern of oligomenorrhea
Infrequent cycles