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Flashcards in Menstrual cycle Deck (36):

What three things must a woman have to have a normal menstrual period?

Normal HPO axis

Responsive endometrium

Patent outflow tract 


When is the clinical dating of the menstrual cycle?

From the first day of the last period


What happens in the preparation phase of the menstrual cycle?

Follicles grow in the ovary

The cervix prepares to allow sperm in (opens)

Uterus proliferates Sexual interaction facilitated


Describe the events of the early follicular phase

Begins as menstrual shedding starts. Oestrogen returns to basal levels Hypothalamus and pituitary free from negative feedback. FSH and LH begin to rise in the absence of negative feedback from oestrogen (FSH raised more due to lack of inhibin). FSH stimulates granulosa cells, and LH stimulates theca cells. Follicles begin to grow


Which hormone is dominant in the mid-follicular phase?

Oestrogen Released by the follicle as it develops and grows


Describe the events of the mid-follicular phase

As follicles grow they secrete oestrogen and inhibin. This exerts negative feedback on FSH and LH. FSH is selectively depressed by inhibin, which means that no more follicles are recruited to mature. FSH falls more than LH. One follicle becomes dominant and matures (antral follicle/ Graafian follicle). 

Motility of the oviduct and myometrium increase to encourage movement of the ova towards the ampulla. 

The endometrium begins to proliferate and the cevix secretes a thin alkaline mucus when open which creates a favourable environment for the sperm. 

Changes occur in vagina secretions, skin, hair and metabolism 




What are the three layers of the uterus?

Endometrium (inner)

Myometrium (outer)

Perimetrium (outer coat)


What are the layers of the endometrium?

Strata functionalis (has compact and spongy layers)




What are the key events at the end of the follicular phase?

One follicle has become dominant (Graafian follicle) and levels of oestrogen rise rapidly, resulting in positive feedback on LH. 

This produces the LH surge required for ovulation


What happens to the uterus in the follicular phase?

It begins to proliferate (endometrium layers grow in preparation for the conceptus)


Describe the changes that occur in ovulation

After the LH surge the Graafian follicle ruptures and the ova is released into the peritoneum (causes mid-cycle pain). Some fluid is also released which can irritate the peritoneum. 

Mid-cycle can occur due to a temporary drop in oestrogen post-ovulation. 


Describe the events of the luteal phase

THe disrupted follicle forms teh corpus luteum. This secretes oestrogen and progesterone. 

LH, FSH and GnRH are suppressed by negative feedback. 

The corpus luteum lasts 14 days and then regresses. This is the least variable part of the cycle. 

The myometrium becomes quiescent and continues to proliferate. 

Cervix secretes a thick acidic mucus which kills any sperm in the vaginal tract. 

There is decreased libido, an increase in temperature, water retention and bloating due to testosterone. 


Describe the events at the end of the luteal phase if the ova is not fertilised

The corpus luteam undergoes apoptosis if fertilisation fails to take place. 

Levels of oestrogen and progesterone fall and the endometerium begins to shed (menstruation)

The pituirary and hypothalamus are freed from feedback inhibition. 

LH anf FSH begin to rise to start a new cycle. 


Describe the events at the end of the luteal phase if there is fertilisation

The conceptus implants into the endometrium and forms trophoblast layers which secretes hCG. 

hCG maintains the corpus luteum to continue to secrete progesterone and oestrogen until the placenta has developed (10-12 weeks)


What are the three classic symptoms of the menopause?

Hot flushes


Vaginal dryness


What is the menopause?

Cessation of the menses. 

Normally occurs between 45-60. Decline is gradual as ovarian oestrogen levels are progressively reduced. Periods space out and cease.  

Symptoms are primarily due to falling oestrogen levels 


Name four other symptoms a women may experience when going through the menopause?

Non-specific: Headaches, migranes, palpitations, disturbed sleep

Urogenital  symptoms: vaginal dryness, cystitis, urinary frequency, urinary incontinence

Psychological: Loss of concentration, poor memory, irritability, loss of libido

Atrophy of connective tissue: skin thinning, hair loss, brittle nails, aches and pains, osteoporosis


What is the normal onset of menarche?

11-15 years


What is the average length of a normal menstrual cycle?

21-42 days


How much blood is lost during menstrual flow?



What are the important things to ask a patient who presents with menstrual problems

Menstrual history:
What is the normal cycle period?
Has there been an increase or decrease in normal flow?
Symptoms of anaemia



Heavy irregular periods


What are the categories of abnormal bleeding?

No bleeding

Abnormal uterine bleeding

Early pregnancy complications


Causes of dysmenorrhea

Painful periods 

Primary: no pathology, due to increased release of prostaglandins. Treated with NSAIDs, time. Common in adolescents

Secondary: occurs in middle reproductive years, pathological e.g. endometriosis



Caused by ectopic endometrial glands and stroma. 

Causes a cyclical pain due to the action of  hormones regulating the menstrual cycle. 

Symptoms include dysmenorrhoea, dyspareunia, irregular periods. 


Causes of amenorrhea

Primary amenorrhoea - no menarche by age 16

Secondary - over 3-6 months with no period. 

Can be physiological or pathologic


Name four physiological causes of amenorrhoea







Name four pathologic causes of amenorrhoea

Hypothalamic control (altered in anorexia and stress)

Pituitary tumor

Dysgenesis ot damage to the ovary

Damage to the uterus

Imperforate hymen


What tests would you do in a patient who is amenorrheic?

Pregnancy test

Oestrogen levels

FSH levels

Hb/Hct levels

Thyroid hormone levels



Name three causes of abnormal uterine bleeding

Endometrial cancer

Cervical cancer


Endometrial polyps


What are fibroids?

The common name for uterine leiomyomas (benign smooth muscle neoplasms) which occur in the myometrium. 

Leiomyomas are well defined, round, firm, gray-white tumors surrounded in a pseudocapsule. Can be submucosal, intramural or subserosal. May be asymptomatic even if extensive. 

Can cause abnormal bleeding, compression of the bladder (causing urinary frequency), pain and impaired fertility. 


Name three causes of bleeding in early pregnacy

Implantation bleeding


Molar pregnacy

Ectopic pregnancy. 


How would you evaluate abnorma bleeding in a patient?

History: general, menstrual 

Physical examination, pelvic examination

Blood tests: hCG, Hb levels


Possible pelvic ultrasound and endometrial sampling


What are the effects of oestrogen in the follicular/proliferative phase?

steadily rising titres of  oestrogen stimulates: 

secretion and muscular contraction in the fallopian tube, and the growth and motility of fallopian cilia

growth and motility of the myometrium

thickening of the endometrium, and secretion a watery fluid to help transport of sperm

 secretion of  thin alkaline cervical mucus 

 increased mitotic activity in the vaginal epithelium

mildly anabolic metabolic changes, depress appetite and affects  the cardiovascular system


What are the actions of progesterone in the luteal/secretory phase?

the action of progesterone on   oestrogen                  primed cells:

Reduces fallopian tube motility, secretion and cilia activity

Stimulates further thickening of the myometrium, but reduces motility

Stimulates further thickening of the endometrium, increased secretion and the development of spiral arteries

Stimulates thickening and acidity f cervical mucus, to prevent sperm transport

Stimulate a mildly catabolic metabolic change and increases basal body temperature


How would you evaluate abnorma bleeding in a patient?

History: general, menstrual 

Physical examination, pelvic examination

Blood tests: hCG, Hb levels


Possible pelvic ultrasound and endometrial sampling