Ovulatory Dysfunction Flashcards
Anovulation or oligo-ovulation account for what percentage of fertility disorders?
30%
Normal ovarian function
Recruitment of follicles
Selection of a dominant follicle
Ovulation
Corpus luteum formation
Follicular phase
Several follicles enlarge under FSH
One becomes dominant
Increasing 17 beta-estradiol is secreted by the granulosa cells surrounding dominant follicle
Rising oestrogen stimulates proliferative growth of endometrium
Negative feedback on FSH (inhibit)
Oestrogen threshold reached, triggers pituitary to cause LH surge plus modest surge of FSH
36 hours after LH surge get ovulation
LH stimulates remaining follicle and granulosa cells to form corpus luteum
Corpus secretes oestrogen and progesteron
Luteal phase
Endometrium develops secretory changes
Corpus maintained by LH initially then b-hcg takes over until the placenta does
If no pregnancy, CL degenerates 4 days prior to menses
Test to confirm ovulation
Day 21 progesterone
Or 7 days before expected period
Group 1 ovulation disorders
Hypothalamic-pituitary failure
10%
Hypothalamic amenorrhoea or
Hypogonadotrophic hypogonadism
Group 2 ovulation disorder
Hypothalamic -pituitary-ovarian dysfunction
85%
PCOS
Group 3 ovulation dysfunction
Ovarian failure
5%
Hypergonadotrophic hypogonadism
Ovarian insufficiency
Symptoms of hypogonadotrophic hypogonadism
Amenorrhoea in the form of absent natural periods
May be slim
Unlikely to be hirsuit
May demonstrate multi-follicular ovaries on a scan, where multiple follicles have started to develop but arrested at different sizes
May have hx of anorexia or excessive exercise
Hx of a brain tumor or treatment
Random FSH and LH are helpful if are repeatedly low
Evidence of oestrogen deficiency
Normal prolactin and TSH
Signs of oestrogen deficiency
Vaginal dryness
Low random oestrodiol levels
Thin endometrium (<5mm)
Absence of a progestogens withdrawal bleed
Osteopenia/osteoporosis on a bone density scan
Test required in all diagnoses of HH
MRI- need to exclude a space occupying lesion
Clomiphene citrate dosing
50 mg daily for 5 days on day 3 of period
Can increase up to 150mg if no evidence of ovulation achieved
Clomiphene mechanism of action
Blocks estrogen receptors in the anterior puituitary, leading to increased secretion of FSH
Letrozole mechanism of action
Aromatase inhibitor
Reduces the amount of estradiol in the ovary and peripheral tissues
Negative feedback stimulates HP axis
GnRH release produces FS
FSH stimulation of follicle
Rising oestrogen level from follicle
Suppresses FSH leaving a single dominant-follicle
Hyperinsulinaemia leading to anovulation
Insulin resistance in PCOS leads to an increase in peripheral insulin levels
Hyperinsulinaemia enhances release of LH from the pituitary as well as ovarian androgen production, leading to follicular arrest and anovulation
Side effects of clomiphene
Flushing Ovulation pain Blurry vision, double vision Moodiness Nausea Breast tenderness Headache Vaginal dryness
Testosterone normal, can exclude
Adrenal pathology
Androgen-secreting pathology
Testosterone elevated and SHEZ elevated then cause likely is…
Adrenal
Elevated 17-OH-progesterone levels suggestive of…
Late onset-CAH
Androstenedione elevated but DHEA normal, testosterone elevated then likely cause is
Ovarian (usually PCOS)
Hypergonadotrophic hypogonadism hormone levels
Low oestrogen
Elevated gonadotrophin
