2. Menstruation Flashcards
Menstrual cycle
- Mensis (month in latin) mene (moon in greek)
- A monthly cyclical process
○ A moon phase cycle is 29.5 days
○ Average menstrual cycle is 28 days - A complex system of hormonal, ovarian and uterine changes across 4 phases
○ Ovulatory
○ Follicular
○ Menstrual
○ Luteal
purpose of menstrual cycle
- Ovulation (release of one egg)
- Preparation of the endometrium (lining) for implantation
- Rare to humans and some primates, bats, mouse and elephant shrew
Hypothalamic pituitary ovarian (HPO) Axis
- Gonadotropin-releasing hormone (GnRH) is responsible for the initiation of puberty and the regulation of hormones involved in female reproduction
- The HPO axis includes both negative and positive feedback mechanisms
1. At beginning of menstrual cycle oestrogen levels are low, GnRH is secreted and stimulates FSH production
2. Rising oestrogen levels inhibit FSH (to stop follicles from developing any further) and stimulate LH secretion to trigger ovulation
3. Once ovulation has occurred, progesterone levels rise and both progesterone and oestrogen inhibit FSH until next cycle - Hypothalamus releases GnRH (triggered by low oestrogen). This stimulates the pituitary gland to releases FSH. Estrogen levels rise and FSH is inhibited while LH secretion is stimulated which triggers ovulation.
- Once ovulation has occurred, progesterone levels rise and progesterone, combined with estrogen inhibit FSH until next cycle
Day 1 to 13/14 of the cycle
follicular phase
- Estrogen and progesterone start low
Menses
- Top layers of thickened lining of uterus break down and shed
- FSH increases slightly, stimulating the development of several follicles in ovaries
Proliferative phase
- Later, as FSH decreases, usually one follicle continues to develop
- The follicle produces oestrogen and levels increase steadily
- Lasts 13 to 14 days typically
- Tends to become shorter near menopause
- Ends when LH surges
Basal body temp is low
Day 14/15
ovulation
- Begins with the surge in LH and FSH
- LH stimulates egg release = ovulation
- estrogen decreases during Gonadotropin surge whiles progesterone start to increase
- Usually lasts 16 to 32 hours
- Ends when egg is released about 10 to 12 hours after LH surge
The fertile window
- Pregnancy can occur 5 days before to 1 day after ovulation
- Actual number of fertile days vary from cycle to cycle and individually
- The egg can be fertilised for 12ish hours after release
Sperm live for 3 to 5 days
Day 14 to 28
luteal phase
- LH and FSH decrease
- Ruptured follicle closes and forms a corpus luteum, which produces progesterone
- Suring most of the phase estrogen is high
- Basal body temp is high
Secretory phase
- Progesterone and estrogen cause lining of the uterus to thicken in preparation for possible fertilisation If egg is not fertilised
- Corpus luteum degenerates and no longer produces progesterone
- Estrogen decreases
- Top layers of lining break down and are shed to make start of new menstrual cycle
- If egg is fertilised Corpus luteum helps maintain early pregnancy
normal menstrual cycle
- Normal to get it below age of 16
- Normal to stop after 45
- Normally lasts 3 to 8 days
- 80ml of less of blood
- 24 - 38 day cycle
- No intermenstrual bleeding
signs of ovulation
- Mucus change, mittelschermz (middle pain), bloating, headache, increase in basal body temperature
- LH surge can be detected in either urine or serum samples
○ Commercial urinary kits are available for home use
○ Helpful for women to plan timed intercourse
~36 hours after the LH surge, the oocyte is released from the follicle into the fallopian tube
Menarche is affected by
- Genetic factors - race
- Environmental conditions - passive smoking
- Body mass index (BMI) - nutrition, physical activity
- Geographic location - urban or rural residence
- Health status - blindness, tea consumption
- Psychological factors - family size, loss of parents, child sexual abuse, physical stress
Menopause is affected by
(aunt Nellie uses big, heavy environmental objects)
- Age at menarche
- Number of pregnancies
- Use of oral contraceptives
- Body Mass Index (BMI) - physical activity
- Health Status - smoking, drinking alcohol
- Environmental conditions - blood lead levels
Other factors
Heavy menstrual bleeding (HMB) previously called menorrhagia
- 20-30% of women of reproductive age, most do not seek help
- Excessive menstrual blood loss that interferes with quality of life and which can occur alone or in combination with other symptoms
- ≥ 80 mL each cycle (difficult to measure)
○ Soaking through ≥ 1 pad or tampon every hour for several consecutive hours
○ Needing to use double sanitary protection
○ Needing to wake up to change sanitary protection during the night
○ Passing blood clots larger than a 10 cent coin - Bleeding for > 7 days
- Symptoms of anaemia, such as tiredness, fatigue or shortness of breath
- Restricting daily activities due to heavy menstrual flow
40–60% of women have no uterine, endocrine, haematological or infective pathology
HMB treatments (I’MMM)
“M” stands for “Medical management”, which may include the use of nonsteroidal anti-inflammatory drugs (NSAIDs), oral contraceptives, progestins, or tranexamic acid to help reduce heavy bleeding.
“M” stands for “Minimally invasive procedures”, such as endometrial ablation or resection, which destroy or remove the lining of the uterus to reduce bleeding.
“M” stands for “Major surgical procedures”, such as hysterectomy, which involves the removal of the uterus and is considered a last resort for treating menorrhagia.
“I” stands for “Intrauterine devices (IUDs)”, such as the levonorgestrel-releasing intrauterine system (LNG-IUS), which can help reduce bleeding.
Amenhorrea (POS)
- absence of menstruation
Primary
- menstruation absent by 16 years
- Physiological - delayed puberty: secondary sex characteristics are also not present by 14 years
- Pathological - hormone disruptions, problems with menstrual outflow, or rare genetic disorders
Secondary amenorrhoea
- previously normal menstruation ceases for 3 months or more
- Physiological – pregnancy, lactation, menopause
- Pathological – hormone disruptions, problems with menstrual outflow
Oligomenorrhoea
- infrequent menstruation (every 35 days to 6 months
- The most common causes of secondary amenorrhoea or oligomenorrhoea are premature menopause, PCOS and hyperprolactinaemia (hormonal)
PMS
- A combination of symptoms (psychological, behavioural and physical)
- experienced during luteal phase (ovulation - menses)
- Associated with dramatic decline in estrogen and progesterone
- Generally self-resolves within few days of period starting, can be managed with overthe-counter pain relief
- About 95% of women will experience PMS at some point in their life *
○ For most it is mild
Tends to worsen approaching menopause
Premenstrual dysphoric disorder PDD (“5-ADP)
- Causes more severe symptoms than PMS, including severe depression, irritability, and tension that disrupts everyday life
- PMDD affects up to 5% of women of childbearing age
- Many women with PMDD may also have anxiety or depression and will require treatment for this and pain relief for the PMS
