Menstrual Cycle

Question 1

GnRH is secreted by the hypothalamus and stimulates the release of what two hormones from the anterior pituitary? What are their roles?

Answer 1

FSH and LH. FSH initiates follicular growth. LH stimulates further development of follicles. Both stimulate the ovarian follicles to secrete oestrogen.

Question 2

The follicles secrete oestrogen and the corpus luteum secretes progesterone. What are the roles of these hormones and when in the cycle is each at its highesT?

Answer 2

Their roles are to prepare and maintain the endometrium for implantation. Oestrogen highest around Day 12 just before LH surge and progesterone gradually rises and falls from day 14-28.

Question 3

The menstrual phase is the first 5 days. What happens in the ovaries?

Answer 3

Primary follicles develop into secondary follicles under the influence of FSH

Question 4

What happens in the uterus in the menstrual phase?

Answer 4

A fall in oestrogen and progesterone stimulates release of prostaglandins causing uterine spiral arterioles to constrict. Cells supplied by these arterioles die and entire stratum functionalis of endometrium falls off leaving the thin stratum basalis.

Question 5

Approx. 50-150 ml of blood, tissue, mucus and epithelial cells is shed through cervix. What is normal amount of blood loss?

Answer 5

5-80ml

Question 6

Preovulatory phase is time between menstruation and ovulation and is most variable phase. What happens in preovulatory phase in the ovaries?

Answer 6

Ovaries: secondary follicles secrete oestrogen. One outgrows the rest become dominant and develops into the graafian follicle.

Question 7

What happens in preovulatory phase in the uterus?

Answer 7

Oestrogens released by follicles stimulate growth of endometrium.
Cells of stratum basalis undergo mitosis to make new stratum functionalis doubling endometrial thickness to 4-10mm.

Question 8

On what day does the ovulatory phase occur?

Answer 8

Day 14 in 28 day cycle or 14 days before menstruation

Question 9

What happens in the ovaries during the ovulatory phase?

Answer 9

Oestrogen stimulates more GnRH release. Leads to increase in LH and FSH. LH causes the rupture of the graafian follicle and expulsion of a secondary oocyte (around 9hrs after LH surge). Oocyte goes to fallopian tube.

Question 10

What happens in the uterus in the ovulatory phase?

Answer 10

Progesterone and oestrogen continue to stimulate proliferation of the endometrium

Question 11

The postovulatory phase routinely lasts for 14 days with little variation and so is the most constant phase. True/false?

Answer 11

True

Question 12

What happens in the ovaries in the postovulatory phase?

Answer 12

Collapsed follicle becomes corpus luteum under LH. Corpus luteum secretes progesterone, oestrogen, relaxin and inhibin. If fertilisation does not occur this secretory activity declines after 2 weeks and new cycle begins

Question 13

What happens in the uterus in the postovulatory phase?

Answer 13

Progesterone and oestrogen promote growth and coiling of endometrial glands, vasculisation and further thickening of endometrium (12-18mm).
Endometrial glands begin to secret glycogen.

Question 14

There should be no more than 9 days difference between the length of a a woman’s shortest cycle and her longest cycle. True/false

Answer 14

True

Question 15

A menstrual cycle is considered “normal” when it lasts how long?

Answer 15

Lasts 24-38 days

Question 16

Bleeding should last __ days or less each cycle to be considered “normal”

Answer 16

8 days or less

Question 17

What percent of women get premenstrual symptoms?

Answer 17

95% women

Question 18

Definition of heavy menstrual bleeding?

Answer 18

Blood loss that interferes with physical, social, emotional or material aspect of a woman’s life

Question 19

What are the investigations for heavy menstrual bleeding?

Answer 19

Exclude pregnancy, Hx and examination , FBC, cervical smear, swabs for infection, USS and if indicated coagulation screen.

Question 20

If there is no abnormality identified or fibroids <3cm causing no distortion of uterine cavity, medical management is started for heavy periods. What is first line for heavy menstrual bleeding?

Answer 20

1st line: mirena coil
2nd line: tranexamic acid or COC
3rd line: norethisterone or DMPA
4th line: surgical

Question 21

What is 2nd line medical management for heavy menstrual bleeding? (w/o abnormality found) What are their mechanisms of action?

Answer 21

Tranexamic acid (antifibrinolytic) or COC (suppresses ovulation and endometrial proliferation)

Question 22

What is 3rd line medical management for heavy menstrual bleeding? (w/o abnormality found) What are their mechanisms of action?

Answer 22

Norethisterone (synthetic progesterone so prevents endometrium proliferation) or DMPA (long acting progesterone so both suppresses ovulation & prevents endometrial proliferation)

Question 23

What is 4th line medical management for heavy bleeding w/o identified abnormality?

Answer 23

surgical management/referral to secondary care

Question 24

What is 1st-4th line medical management of heavy menstrual bleeding w/o identified abnormality?

Answer 24

1st line: mirena coil
2nd line: tranexamic acid or COC
3rd line: norethisterone or DMPA
4th line: surgical

Question 25

20-30% of heavy menstrual bleeding is caused by fibroids. What are they?

Answer 25

very common benign smooth muscle tumours of the uterus

Question 26

5-10% of heavy menstrual periods are caused by polyps. What are they and how may they be diagnosed?

Answer 26

Endometrial or endocervical overgrowths of endometrial tissue. May be diagnosed on speculum exam, USS or hysteroscopy

Question 27

5% of heavy menstrual bleeding is caused by adenomyosis. What is adenomyosis?

Answer 27

Basically is endometriosis within muscle layer i.e. Is the presence of non-neoplastic endometrial glands and stroma in the myometrium so there is myometrial hyperplasia and hypertrophy.

Question 28

Adenomyosis is associated with what PMH? (6)

Answer 28

History of. /section,
uterine curettage, 
surgical TOP, 
increasing age, 
oestrogen exposure,
tamoxifen use

Question 29

What is a rarer cause of heavy menstrual bleeding and what is most common type of this?

Answer 29

Coagulopathy, most common is von Willebrand disease.

Question 30

What are surgical options for heavy menstrual bleeding? (5)

Answer 30

polyps - polypectomy, 
endometrial ablation, 
uterine artery embolisation, 
myomectomy, 
hysterectomy

Question 31

Based on a 28 day cycle, outline the days of the menstrual, proliferative and secretory phases?

Answer 31

Menstrual: D1-7, Proliferative: 7-14, Secretory: 14-28

Question 32

What hormones are responsible for each phase of the uterine cycle? (Proliferative, secretory, menstrual, fertilised)

Answer 32

Proliferative: oestrogen, Secretory: Progesterone, Menstrual: withdrawal of hormones due to collapse of corpus luteum, fertilised: progesterone then HCG

Question 33

What is the Graafian follicle?

Answer 33

The dominant follicle containing the oocyte which is surrounded by granulosa cells that secrete oestrogen and progesterone

Question 34

What are the 3 phases of the uterine cycle of the menstrual cycle?

Answer 34

Menstrual phase, proliferative phase, secretory phase

Question 35

At what day of the luteal phase does corpus luteum start to degenerate if oocyte not fertilised?

Answer 35

Day 10