Menstrual Physiology and Dysfunction Flashcards
Phases of the ovarian cycle and uterine cycle?
ovarian: follicular, ovulation, luteal
uterine: menstrual, proliferative, secretory
Describe the follicular phase of the ovarian cycle?
Primordial follicles are arrested at prophase 1. FSH from the anterior pituitary stimulates a number of primordial follicles to begin maturation. As they mature granulosa cells increase in size and number and secrete oestrogens which drives the cycle.
Describe the ovulation phase of the ovarian cycle?
After about 13 days a dominant follicle develops and increases in size. LH surge leads to ovulation.
Describe the luteal phase of the ovarian cycle?
The left behind follicle partially collapses and forms the corpus luteum. The corpus luteum secretes oestrogen and progesterone. If no fertilisation occurs the corpus luteum regresses so progesterone secretion falls, the endometrial lining is shed and the cycle can begin again.
Describe what happens after the luteal phase if pregnancy occurs?
If fertilisation occurs HCG production from the trophoblast maintains corpus luteum formation until 10-12 weeks of gestation by which time the placenta will be making sufficient oestrogen and progesterone to support iteself.
The menstrual phase of the uterine cycle occurs on days ______ is due to ________ and results in _______
1-3
withdrawal of hormones
shedding of the endometrial lining
The proliferative phase of the uterine cycle occurs on days ______ is due to ________ and results in _______
1-14 (begins at menstruation)
oestrogen
growth of the endometrial glands and stroma
The secretory phase of the uterine cycle occurs on days ______ is due to ________ and results in _______
16-28
progesterone
glandular secretory activity, decidualisation (changes to cells for preparation of pregnancy) and then endometrial apoptosis causing subsequent menstruation
Granulosa cells secrete _______
oestrogens and progesterones
Thecal cells are stimulated by _______ to secrete ______
LH to secrete ovarian androgens
Which phase of the ovarian cycle causes variation in length of cycle?
follicular phase is variable in length luteal phase is fairly constant at 14 days
Explain the endocrinology behind the menstrual cycle?
1) pulses of GnRH at about 2hr intervals stimulates FSH and LH release from the anterior pituitary
2) LH stimulates theca cells to produce androgens
3) FSH stimulates growth of ovarian follicles and associated rise in oestrogen causing reduction in FSH by negative feedback
4) When oestrogen reaches a certain concentration it exerts positive feedback resulting in an increase in FSH and LH surge
5) LH surge causes ovulation and regulates the formation of the corpus luteum which secretes progesterone and oestrogen so FSH and LH fall due to negative feedback on GnRH pulsatility
6) oestrogen initially then progesterone cause endometrial proliferation but if no implanatation the corpus luteum regresses, progesterone falls, menstruation occurs
7) fall in progesterone results in increased GnRH and FSH so cycle can begin again
Timing of ovulation can be predicted reasonably accurately by ________
LH surge which usually occurs 34-36 hrs before
Define menorrhagia?
prolonged and increased menstrual flow
Define metrorrhagia?
regular intermenstrual bleeding
Define polymenorrhagia?
increased bleeding and frequent cycle
Define polymenorrhoea?
menses occurring at <21 days apart
Define menometrorrhagia?
prolonged menses and intermenstrual bleeding
Define amenorrhoea?
absence of menstruation of > 6 months (primary = a girl who doesnt have a period by 16 secondary = absence of period in someone who previously had them)
Define oligomenorrhoea?
menses at intervals of > 35 days
List some local organic causes of menorrhagia?
- fibroids (leiomyoma)
- adenomyosis (endometrial tissue in the myometrium)
- endocervical or endometrial polyp
- cervical eversion
- endometrial hyperplasia
- intrauterine contraceptive device
- pelvic inflammatory disease
- endometriosis
- malignancy of cervix or uterus
- hormone producing tumours
- trauma
- AVM of the endometrium (rare)
List some systemic organic causes of menorrhagia?
hypothyroidism, prolactin disorders, adrenal disease, diabetes mellitus, bleeding disorders, PCOS
List some complications of pregnancy that can cause menorrhagia?
miscarriage, ectopic pregnancy, gestational trophoblastic disease, post partum haemorrhage
Treatment of organic causes of menorrhagia?
treat the underlying condition
What is dysfunctional uterine bleeding?
abnormal uterine bleeding with no underlying organic cause, diagnosis of exclusion usually caused by some form of hormonal imbalance
Dysfunctional uterine bleeding encompasses _____ % of women with abnormal uterine bleeding
50
What are the two types of dysfunctional uterine bleeding? What is more common
anovulatory
ovulatory
anovulatory more common- 85% of all DUB
Describe anovulatory DUB?
85% of all DUB, irregular cycle, occurs at extremes of reproductive life, more common in obese women
Describe ovulatory DUB?
more common in women aged 35-45yo, regular heavy periods, due to inadequate progesterone production by the corpus luteum (eggs and therefore corpus lute is lower quality in older women so don’t get as good progesterone levels)
Investigation of DUB?
FBCS Cervical smear TSH Coagulation screens Renal function LFTs Transvaginal US Pipelle biopsies
List some of the medical management for DUB?
oral progesterones COCP Tranexamic acid Mefenamic acid GnRH analogues Mirena coil
Describe oral progesterone in treatment of DUB?
taken on days 6-26 of the cycle as progesterone stops bleeding then get withdrawal bleeding, this is not contraceptive
Describe COCP in treatment of DUB?
makes period lighter and regular, acts as a contraceptive, contraindicated in women with risk factors for thromboembolism, breast cancer, smokers > 35 yrs and obese women
Describe tranexamic acid as a treatment of DUB?
antifibrinolytic, causes 50% reduction in HMB
Describe mefenamic acid as a treatment of DUB?
is a type of NSAID, it works because the endometrium produces a lot of prostaglandins during menstruation
Describe GnRH analogues as a treatment of DUB?
these produce a reversible state of menopause by down regulating FSH and LH, they are very effective but cant be used long term due to risk of osteoporosis
Describe the mirena coil as a treatment of DUB?
very effective IUD, should be considered in majority as an alternative to surgery
Describe use of hormonal agents vs non hormonal for DUB medical treatment?
most agents are contraceptive or not recommended in pregnancy so would have to stop if wanted to get pregnant
if the patient has a regular cycle may use non hormonal treatment, if irregular use hormonal treatment
When is surgery for DUB considered?
if tried both drug treatment and the coil
Describe endometrial ablation for DUB?
this is usually considered first
there are much fewer complications, shorter recovery
need smear tests as cervix remains
required combined HRT as microscopic endometrium may be left behind and if no progesterone was given there would be an increased risk of endometrial carcinoma
may get monthly spotting due to small bit left over
Describe hysterectomy for DUB?
major operation more complications 100% amenorrhoea if total no cervical smears required oestrogen only HRT (unless cervix remains)
Describe maintaining fertility in medical treatments of DUB vs surgical?
medical maintains fertility (although having to stop taking them)
surgery makes you infertile (with ablation technically can get pregnant but very unsafe so generally they sterilise the women when they do the ablation)
