The Menstrual Cycle And Menstrual Disorders Flashcards
Which 2 cycles run in parallel during the menstrual cycle?
Ovarian and uterine
What is the average length of the menstrual cycle?
28 days (+-7)
Why is GnRH released in a pulsatile manner from the HPO axis?
Persistent presence leads to desensitisation of receptors on gonadotrophs
Which GnRH analogues is used to treat endometriosis infertility?
Decapeptyl (Triptorelin pamoate)
Which two phases make up the ovarian cycle?
Follicular phase,
Luteal phase.
What occurs in the early follicular phase (days 0 to 5)?
No ovarian hormone production,
1.Granulosa cells secrete activin,
2.FSH levels rise, stimulating follicle growth.
(Less androgens are produced by theca cells at this stage)
3. Theca interna appears
4. Follicle is now capable of producing oestrogen
5. Dominant follicle granular cells switch to produce inhibin
What happens during the late follicular phase (days 5-14)
- Dominant follicle granulosa cells produce oestrogen and inhibin
- Oestrogen exerts negative feedback on HPA to reduce FSH production
- increase in LH receptors in granulosa cells
- Oestrogen and inhibin continue to rise
What happens on day 14 of the ovulatory phase?
- Oestrogen levels rise independent of FSH
- High levels of oestrogen exert positive feedback on HPA
- Surge in LH
- Ovulation
- Granulosa cells start secreting progesterone
What occurs in the luteal phase?
- Corpus luteum forms,
- Oestrogen and progesterone secreted in large quantities,
- Presence of progesterone causes oestrogen to exhibit negative feedback on LH
How long is the lifespan of the corpus luteum?
14 days (+-2)
What three phases makeup the uterine cycle?
Menstrual, proliferative, secretory
What occurs at the menstrual phase of the uterine cycle?
Thickened endometrial wall is shed, degredation of corpus luteum to corpus albicans
What happens in the proliferative phase of the uterine cycle?
Which hormone primarily stimulates this?
Thickening of the endometrial layer, coiling of glands.
Oestrogen.
What happens during the secretory phase of the uterine cycle?
Further thickening of the endometrial lining, increased depth and motility of the myometrium, glands and arterioles fully coil.
What do spiral arteries form if implantation occurs?
The placenta
What happens if fertilisation occurs at a hormonal level?
Syncytiotrophoblast prduces hCG
Lifespan of the corpus luteum extends and releases oestrogen and progesterone until the development of the placenta
What are the actions of oestrogen?
Thickening of endometrium, growth and motility of myometrium, vaginal changes, skin changes, regulates osteoclast bone resorption, deposit fat around hips and gluteals, breast tissue proliferation.
What are the actions of progesterone?
Further thickening of endometrium, Thickening of myometrium and reduction of motility, Development of breast tissue, Increase in metabolism and appetite, Increased body temperature, Increased sodium and water retention
How is primary amenorrhea defined?
Failure of menstruation by the age of 16 or by the age of 14 in the abscence of other evidence of puberty
How is secondary amenhorrhea defined?
Absent periods for 6 months in a woman who previously had regular periods, or 12 months if previous oligomenorrhea
How is oligomenorrhea defined?
Infrequent menstruation, such as only occurring between 4-9 times per year
How is menorrhagia quantified?
If bothering the patient, if greater than 80ml, if a significant increase in pad/tampon use.
What is dysmenorrhoea?
What is the most common pathological cause?
Pain at time of menstrual bleeding.
Endometriosis.
What are causes for primary amenorrhea?
Imperforate hymen, Absent vagina or uterus, HPA dysfunction, Turner syndrome, Poor gonadal response to HPA - complete androgen insensitivity syndrome
What is Turner syndrome?
(45X0) phenotype resulting in a lack of secondary characteristics due failure of the ovary to develop
May present as short, prepubescent and with poor mental development.
Lab indicates low estradiol with high FSH and LH
What is complete androgen insensitivity syndrome?
X linked recessive disorder,
Resistance to testosterone due to defects in the androgen receptor.
46XY with female phenotype. Abscence of vagina uterus and Fallopian tubes.
Testes should be surgically excised
What is Kallman syndrome?
GnRH deficiency with associated anosmia (loss of sense of smell)
What causes secondary amenorrhea?
Cervical stenosis
Scarring
Asherman syndrome (intrauterine adhesions)
Primary ovarian insufficiency - premature menopause
Weight loss
Stress
PCOS
What is PCOS?
Poly cystic ovary syndrome, cause elevated LH and raised insulin resistance.
Triad - menstrual irregularity, androgen excess, obesity
What causes oligomenorrhea?
PCOS,
ovarian insufficiency,
Thyroid dysfunction,
Hormonal contraceptives.
What is a common cause of menorrhagia?
Fibroids (leiomyoma)
What is endometriosis?
What common sites are affected?
Ectopic uterine tissue that responds to hormonal changes.
Ovaries, bladder, rectum.
How is dysmenorrhea managed?
NSAIDS and hormonal contraceptives
