The Menstrual Cycle And Menstrual Disorders

Question 1

Which 2 cycles run in parallel during the menstrual cycle?

Answer 1

Ovarian and uterine

Question 2

What is the average length of the menstrual cycle?

Answer 2

28 days (+-7)

Question 3

Why is GnRH released in a pulsatile manner from the HPO axis?

Answer 3

Persistent presence leads to desensitisation of receptors on gonadotrophs

Question 4

Which GnRH analogues is used to treat endometriosis infertility?

Answer 4

Decapeptyl (Triptorelin pamoate)

Question 5

Which two phases make up the ovarian cycle?

Answer 5

Follicular phase,

Luteal phase.

Question 6

What occurs in the early follicular phase (days 0 to 5)?

Answer 6

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

Question 7

What happens during the late follicular phase (days 5-14)

Answer 7

1. Dominant follicle granulosa cells produce oestrogen and inhibin
2. Oestrogen exerts negative feedback on HPA to reduce FSH production
3. increase in LH receptors in granulosa cells
4. Oestrogen and inhibin continue to rise

Question 8

What happens on day 14 of the ovulatory phase?

Answer 8

1. Oestrogen levels rise independent of FSH
2. High levels of oestrogen exert positive feedback on HPA
3. Surge in LH
4. Ovulation
5. Granulosa cells start secreting progesterone

Question 9

What occurs in the luteal phase?

Answer 9

1. Corpus luteum forms,
2. Oestrogen and progesterone secreted in large quantities,
3. Presence of progesterone causes oestrogen to exhibit negative feedback on LH

Question 10

How long is the lifespan of the corpus luteum?

Answer 10

14 days (+-2)

Question 11

What three phases makeup the uterine cycle?

Answer 11

Menstrual, proliferative, secretory

Question 12

What occurs at the menstrual phase of the uterine cycle?

Answer 12

Thickened endometrial wall is shed, degredation of corpus luteum to corpus albicans

Question 13

What happens in the proliferative phase of the uterine cycle?
Which hormone primarily stimulates this?

Answer 13

Thickening of the endometrial layer, coiling of glands.

Oestrogen.

Question 14

What happens during the secretory phase of the uterine cycle?

Answer 14

Further thickening of the endometrial lining, increased depth and motility of the myometrium, glands and arterioles fully coil.

Question 15

What do spiral arteries form if implantation occurs?

Answer 15

The placenta

Question 16

What happens if fertilisation occurs at a hormonal level?

Answer 16

Syncytiotrophoblast prduces hCG

Lifespan of the corpus luteum extends and releases oestrogen and progesterone until the development of the placenta

Question 17

What are the actions of oestrogen?

Answer 17

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.

Question 18

What are the actions of progesterone?

Answer 18

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

Question 19

How is primary amenorrhea defined?

Answer 19

Failure of menstruation by the age of 16 or by the age of 14 in the abscence of other evidence of puberty

Question 20

How is secondary amenhorrhea defined?

Answer 20

Absent periods for 6 months in a woman who previously had regular periods, or 12 months if previous oligomenorrhea

Question 21

How is oligomenorrhea defined?

Answer 21

Infrequent menstruation, such as only occurring between 4-9 times per year

Question 22

How is menorrhagia quantified?

Answer 22

If bothering the patient, if greater than 80ml, if a significant increase in pad/tampon use.

Question 23

What is dysmenorrhoea?

What is the most common pathological cause?

Answer 23

Pain at time of menstrual bleeding.

Endometriosis.

Question 24

What are causes for primary amenorrhea?

Answer 24

Imperforate hymen,
Absent vagina or uterus,
HPA dysfunction,
Turner syndrome,
Poor gonadal response to HPA - complete androgen insensitivity syndrome

Question 25

What is Turner syndrome?

Answer 25

(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

Question 26

What is complete androgen insensitivity syndrome?

Answer 26

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

Question 27

What is Kallman syndrome?

Answer 27

GnRH deficiency with associated anosmia (loss of sense of smell)

Question 28

What causes secondary amenorrhea?

Answer 28

Cervical stenosis
Scarring
Asherman syndrome (intrauterine adhesions)
Primary ovarian insufficiency - premature menopause
Weight loss
Stress
PCOS

Question 29

What is PCOS?

Answer 29

Poly cystic ovary syndrome, cause elevated LH and raised insulin resistance.
Triad - menstrual irregularity, androgen excess, obesity

Question 30

What causes oligomenorrhea?

Answer 30

PCOS,
ovarian insufficiency,
Thyroid dysfunction,
Hormonal contraceptives.

Question 31

What is a common cause of menorrhagia?

Answer 31

Fibroids (leiomyoma)

Question 32

What is endometriosis?

What common sites are affected?

Answer 32

Ectopic uterine tissue that responds to hormonal changes.

Ovaries, bladder, rectum.

Question 33

How is dysmenorrhea managed?

Answer 33

NSAIDS and hormonal contraceptives