Menstrual cycle Flashcards
What are the events in the folecular phase of the ovarian cycle ?
- At the beginning of the menstrual cycle, levels of FSH rise causing stimulation of a few ovarian follicles.
- As follicles mature they compete with each other for dominance.
- The first follicle that becomes fully mature begins to produce large amounts of oestrogen.
- Oestrogen inhibits the growth of the other competing follicles.
- The single follicle that reaches full maturity during this process is referred to as the Graafian follicle (the oocyte develops within this).
- The Graafian follicle continues to secrete increasing amounts of oestrogen.
- Increasing amounts of circulating oestrogen results in: (1) endometrial thickening, (2) thinning of the cervical mucus to allow easier
passage of sperm , (3) inhibition of LH production by the pituitary gland - As oestrogen levels rise, they eventually surpass a threshold level, at which point they conversely stimulate LH production, resulting in
a spike in LH levels around day 12. - The high amounts of LH cause the membrane of the Graafian follicle to become thinner.
- Within 24-48 hours of the LH surge, the follicle ruptures releasing a secondary oocyte.
- The secondary oocyte quickly matures into an ootid and then into a mature ovum.
- The mature ovum is then released into the peritoneal space and is taken into the fallopian tube via fimbriae.
What are the events in the Luteal phase ?
- Once ovulation has occurred LH and FSH stimulate the remaining Graafian follicle to develop into
the corpus luteum. - The corpus luteum then begins to produce the hormone progesterone.
- Increased levels of progesterone result in:
(1) The endometrium becoming receptive to implantation of the blastocyst
(2) Negative feedback causing decreased LH and FSH (both needed to maintain the corpus luteum)
(3) An increase in the woman’s basal body temperature - As the levels of FSH and LH fall, the corpus luteum degenerates.
- Degeneration of the corpus luteum results in loss of progesterone production.
- The subsequent falling level of progesterone triggers menstruation and the entire cycle begins
again.
During pregnancy continued production of _______ prevents menstruation.
Progesterone
What are the events in the proliferative phase of Uterine cycle ?
- The endometrium is exposed to high levels of oestrogen produced through FSH and LH mediated mechanisms.
- Oestrogen facilitates the repair and regeneration of endometrium by increasing the number of secretory glands, generation of spiral arteries, and increasing the thickness of endometrium.
What are the events in the secretory phase of Uterine cycle ?
In this phase progesterone produced by the corpus luteum triggers release of various substances by the endometrial glands inorder to prepare the uterus ready for implantation.
What are the events in the menstrual phase of Uterine cycle ?
In this phase Corpus luteum degenerates which results in decreased progesterone production, leading to degeneration of spiral arteries in the functional endometrium. The functional endometrium becomes ischemic and necrotic and sheds as menstruation.
What is the definition of oligoamnorrhoea and what is its common cause ?
- Oligomenorrhea, or infrequent periods, is when the menstrual cycle is longer than 35 days.
- The commonest cause of oligomenorrhea is polycystic ovarian syndrome, which affects 10% of women.
What is the effect of less than 4 periods in a year ?
the risk of endometrial hyperplasia
and cancer increases.
What is the ESHRE dx criteria for PCOS ?
*Anovulation (low progesterone level on blood tests) or irregular cycles (> 35-day cycle)
* Clinical hyperandrogenism, including acne and hirsutism
* Hyperandrogenism on hormonal profile blood tests, including testosterone and androstenedione
* Polycystic ovaries on ultrasound scan
What are the elements of female athlete triad ?
- Low energy availability
- Low bone mineral density
- Menstrual disturbances.
What is endometriosis ?
- Endometriosis is the ectopic occurrence of endometrial tissue outside the uterus.
- It is a chronic, recurring, and progressive condition that affects 2–10% of women
in Ireland and affects up to 50% of women with infertility. It is under-recognized and under-treated.
What are the symptoms of endometriosis ?
- Common symptoms of endometriosis include dysmenorrhea, heavy menstrual
bleeding, pelvic pain, and dyspareunia. - Other symptoms include dyschezia and dysuria.
What are the PE findings in endometriosis ?
- The vaginal examination may demonstrate a fixed retroverted uterus, nodules or
thick uterosacral ligaments, or an ovarian cyst (endometrium).
What are the investigations in endometriosis ?
- Pelvic US to rule out other pathologies such as adenomiosis and fibroids. The endomteriosis can also be seen sometimes.
- MRI pelvic to diagnose endometriosis including deeply infiltrating endometriosis
- AMH level should be if fertility is desired
- Cancer antigen CA125 should be checked if there are ovarian cysts. It is elevated in endometriosis.
What are the patient priorities for woman with endometriosis ?
- Pain control to improve QL
- Definitive diagnosis and fertility
What is the first line Tx of Menorrhagea ?
Levanorgestrel IUS is the first line choice. It is licensed for 5 year duration of delivery of prgesterone to prevent menorrhogea, but has enough hormone for 7 years. It releases 20 mg progesterone/ day and 99% acts only locally.
What are the non-hormonal Tx in Menorrhogea ?
- Mefanamic acid 500 mg TDS which reduce bleeding by 30 to 40% and reduce dismenorrhoea.
- Tranexamic acid- 500 mg TDS reduces bleeding by 40 to 50% and can be given for 5 days if there is no renal compromise.
What are the surgical options in Menorrhogea ?
- Endometrial ablation in woman whose family is complete and do not want IUS.
- Myomectomy for fibroid removal and Submucosal fibroids can be removed histeroscopiclaly or laproscopically.
- MRI guided fibroid embolization.
- Hysterectomy.
What age group has the highest prevalence of cervical cancer and what are the strains ?
under the age of 25 with HPV 16 or 18.
