Menstrual cycle and disorders Flashcards
Explain the hormonal processes in menstrual cycle
- Days 1-4 - the endometrium is shed as hormonal support is withdrawn.
- 5-13 - proliferative stage.
- GnRH pulses from hypothalamus stimulate LH and FSH from pituitary which causes follicles to mature.
- Follicles produce oestrodiol and inhibin which causes negative feedback on FSH to prevent multiple follicles maturing.
- Ostrodial and inhibin cause positive feedback on LH, causing an LH surge.
- Ovulation occurs 36 hours after LH surge.
- Oestrodial causes endometrium to re-form and become ‘proliferative’ - it thickens as stromal cells proliferate and glands elongate. - 14-28 - Luteal phase
- Corpus luteum produces oestrodial, but relatively more progesterone.
- Progesterone levels peak a week later (day 21)
- Progesterone induces secretory changes in the endometrium where stromal cells enlarge, glands swell and blood supply increases.
- Towards the end of luteal phase the corpus luteum starts to fail if the egg is not fertilised, causing progesterone and oestrogen levels to fall.
- Endometrium is shed.
What day in the menstrual cycle does progesterone peak?
Day 21
What does FSH and LH cause follicles to produce?
Inhibin and oestrodial
How long after LH surge does ovulation occur?
36 hours
In a 28 day cycle, when is the LH surge?
Day 13
Define irregular menstrual bleeding
Cycle-to-cycle variation of >20 days
Define amenorrhoea
No bleeding in a 6-month period
Define prolonged and shortened menstrual bleeding
Prolonged is longer than 8 days
Shortened is shorter than 3 days
State the causes of abnormal uterine bleeding
PALM COEIN
Polyps
Adenomyosis
Leiomyomas (fibroids - submucosal/other)
Malignancy and hyperplasia
Coagulopathy Ovulatory dysfunction Endometrial Iatrogenic Not yet specified
What is heavy menstrual bleeding?
Excessive menstrual blood loss that interferes with the woman’s physical, emotional, social and material quality of life, and which can occur alone or in combination with other symptoms.
Blood loss of >80mL –> this is the max amount a woman can lose in an otherwise normal cycle without becoming iron deficient on a normal diet.
Investigations into heavy menstrual bleeding
Examination - pain suggests adenomyosis, irregular enlargement of the uterus suggests fibroids
Haemoglobin checked
Coagulation and thyroid function checked
Trans-vaginal ultrasound of the pelvis (saline ultrasound)
Endometrial biopsy should be considered
First, second and third line medical treatments of heavy menstrual bleeding
1st
- IUD (intrauterine progesterone)
2nd line
- antifibrinolytics (tranexamic acid - taken during menstruation only and can reduce bleeding by 50%),
- NSAIDs (inhibits prostaglandin synthesis, reducing blood loss by 30%)
- COCP
3rd
- Progestogens taken in high doses orally or intramuscularly (causes amenorrhoea)
- GnRH analogues - can only be taken for 6 months.
What is the normal endometrial thickness in a premenopausal woman?
From 4mm in follicular phase up to 16mm in luteal phase.
Surgical treatments of heavy menstrual bleeding
- Polyp removal
- Endometrial ablation (reduces fertility but not sterilising so need contraception. Uses thermal balloons, microwave, cryotherapy or radiotherapy energy delivered by the cervix to heat and destroy the endometrium.)
- Trans-cervical resection of a fibroid (submucosal fibroids are resected to reduce menstrual flow and improve fertility).
- Myomectomy - removal of fibroids from the myometrium, usually given a course of GnRH agonists to reduce the size of fibroids.
- Hysterectomy
When do you do an endometrial biopsy?
Age >40 years
HMB with intermenstrual bleeding
Risk factors for endometrial cancer (obesity, PCOS, diabetes, nulliparity, family history of hereditary non-polyposis colorectal cancer)
HMB unresponsive to treatment
If ultrasound suggests a polyp or focal endometrial thickening
Prior to endometrial ablation (as tissue will not be viable after)
If abnormal uterine bleeding has resulted in acute admission.
