Obstetrics Flashcards
What are the normal pH ranges at delivery for uterine artery and vein samples during cord gases?
Uterine vein (reflects maternal status and placental function): pH 7.2 - 7.44)
Uterine artery (reflects fetal status): pH 7.1 - 7.38
What does the FIGO classification for abnormal uterine bleeding PALM-COEIN stand for?
P: Polyps
A: Adenomyosis
L: Leiomyoma (ie fibroids)
M: Malignancy (endometrial, cervical, ovarian)
C: Coagulopathy
O: Ovulatory dysfunction
E: Endometrial
I: Iatrogenic
N: Not yet classified
Is the luteal phase fixed at 14 days, true or false?
True. The lifespan of the corpus luteum is 14 days
Which age group has the highest variability in menstrual cycle length on average?
<25 year olds have the highest menstrual cycle length variability. Variability declines to be at the lowest in the 35-39 age category. Variability then slightly increases again in the 40-44 category.
Menstrual cycles tend to get shorter with age, true or false?
True.
What is the ‘normal’ menstrual blood loss per cycle?
25-50ml is considered normal. Menstrual blood loss equal or greater than 80ml is considered abnormal (HOWEVER when defining HMB clinically, impact on physical / emotional / quality of life is the definition. the use of >80ml per cycle should only be used for research work)
A 32-year-old woman presents with symptoms of menorrhagia, dysmenorrhoea and cyclical, localised pelvic pain. The pelvic ultrasound showed no abnormality. What is the next appropriate investigation?
Laparoscopy
Allows diagnosis +/- ablation therapy for endometriosis in younger females with cyclical pelvic pain + dysmennhorea + menorrhagia and a normal USS.
What 2 investigations are pre-requisities before performing uterine artery embolisation on fibroids?
1) Hysteroscopy
2) MRI pelvis
What is the first-line diagnostic tool for the identification of structural pathology in women with HMB?
Transvaginal / transabdominal USS
What is the next appropriate investigation for postmenopausal bleeding with abnormal endometrial thickness on USS?
Urgent outpatient hysteroscopy + endometrial biopsy
Which specific test, additional to routine screening, is undertaken on women with HMB in their teenage years or who have had HMB since menarche
Testing for coagulation disorders, including von willebrand’s disease
What are contraindications for endometrial ablation?
Endometrial ablation is lower risk (but has ~ 20% risk of inadequate resolution leading to eventual hysterectomy) than hysterectomy for those women that suffer with HMB resistant to medical treatment and that do not wish for further children. Contraindications to ablation are;
- Large uterus - either >12 weeks in size or >12 cm in length - not an absolute contraindication but the chance of success lower
- Submucosal fibroid/s >2cm
- Any non-benign endometrial pathology
- Cervical cancer
- Current pelvic infection
- If hysterectomy is required for another condition
What are the 4 features of a menstrual cycle that you should assess and what are the ‘normal’ (5th - 95th centile) values for them?
Frequency - should be between every 24-38 days
Variability - there should be max 7-9 days variability between the shortest and longest cycles
Duration - 4-8 days of bleeding per cycle
Volume - subjective, but 25-50ml considered normal, >80 is heavy
What are the different sub-divisions of intermenstrual bleeding (IMB)?
- Cyclic mid-cycle IMB - regular midcycle bleed that can be physiological due to the trough in oestrogen at the time of ovulation
- Cyclic pre or post menstrual IMB - bleeding that cyclically occurs either in the follicular phase or in the luteal phase
- Acyclic IMB - IMB that is not cyclical / predictable
Definition of infrequent periods?
Periods every >38 days
Definition of frequent periods?
Periods every 23 days or less
Definition of irregular periods?
10 or more days variation in menstrual cycle lengths
Definition of prolonged menses?
> 8 days bleeding per cycle
Acute versus chronic non-gestation AUB?
Acute is a one-off episode of abnormal uterine bleeding whereas chronic is an abnormality in frequency, variability, duration or volume that has been present for the majority of the last 6 months or more.
What are polyps?
Polyps = localised overgrowth of endometrial stroma and gland tissue. Can be endometrial or endocervical. Can be pedunculated or sessile (flat). Tend to be smaller than fibroids. Don’t tend to be painful. Can cause irregular periods + IMB / spotting.
What are the 3 layers of the uterine wall?
Endometrium, myometrium and perimetrium
What is adenomyosis? What are it’s presenting symptoms and what are the classical US findings?
Adenomyosis = growth of endometrial tissue within the myometrial layer. Tends to present with dysmennorhoea + menorrhagia and an enlarged, tender uterus.
TVUS shows a globular enlarged uterus, heterogenous echogenicity of the myometrium, loss of clarity of the endo-myometrial junction + linear striations.
What are known risk factors for adenomyosis?
Factors that disrupt the endo-myometrial junction (= ^ parity, prev LSCS, prev TOP, uterine curettage) and prolonged oestrogen exposure (advancing age, prev tamoxifen use)
SMOKING MAY BE PROTECTIVE
what are fibroids and how do they typically present?
Fibroids are benign smooth muscle tumours of the myometrium. They typically grow larger than polyps, are extremely common (>80% in black women + >70% in white women by age 50), result in prolonged + painful periods and chronic pelvic pain and pressure symptoms.
As women get older there is small but significant risk of malignant transformation of fibroids into leiomyosarcomas = uterine sarcomas arising within a fibroid and presenting with AUB and more rapid fibroid growth. Incidence of uterine sarcoma is essentially non-existent <45 and only ~0.5% in peri and post menopausal women.
What are the major risk factors for endometrial hyperplasia and malignancy?
Unopposed exposure to oestrogen + prev Tamoxifen use.
Family history of endometrial, breast or colon cancer
Nulliparity
Late menopause
Obesity
PCOS
Diabetes + hypertension
What features of presentation / investigation in a women with AUB would make you suspect a primary endometrial disorder (AUB-E)?
Primary endometrial dysfunction should be considered in women with HMB but regular cycles and a structurally normal uterus and normal clotting. Unknown pathophysiology but may be related to abnormal local haemostasis.
What are the 4 main categories of medications that are commonly implicated in iatrogenic AUB?
1) Exogenous sex steroids, especially progesterone-only preparations
2) Drugs that alter hepatic enzyme activity which can affect circulating sex steroid levels (anti-epileptics and anti-TB drugs)
3) Anti-coagulants + anti-platelets
4) Tricyclic antidepressants eg amitriptyline - alter dopamine levels = hyperprolactinaemia = anovulation
What is an isthmocoele?
A uterine defect at the site of a previous LSCS incision that can sometimes be a cause of ‘not otherwise classified’ AUB
What are the routine 1st line investigations that should be carried out in primary care for women presenting with HMB?
Gynae and general Hx
Exclude pregnancy
FBC to assess for anaemia
Coag screen + VWF if positive response to screening questions or HMB since menarche
Speculum exam with cervical smears + pelvic infection swabs as appropriate
Bimanual examination to assess for pelvic masses / tender / bulky uterus
Request pelvic USS as 1st line if no obvious evidence or strong risk factors for polyps or endometrial malignancy
If polyps / endometrial pathology suspected then outpatient hysteroscopy +/- endometrial biopsy should be 1st line.
USS is more accurate at identifying uterine fibroids than hysteroscopy whereas hysteroscopy is better at identifying polyps and endometrial pathology.
What are the ‘red flag features’ in HMB that warrant referral to one-stop or rapid access gynae clinic?
1) Suspected malignancy (persistent intermenstrual / post-coital bleeding / post-menopausal bleeding, cervical lesion or pelvic mass = urgent referral, within 2 weeks)
2) Endometrial biopsy required to exclude endometrial hyperplasia / malignancy (persistent AUB, >45 with treatment failure, irregular bleeding on hormone replacement or tamoxifen)
3) Enlarged uterus (>10weeks clinically or > 10cm on uss)
4) Moderate / Severe anaemia
5) Uterine / ovarian pathology noted on USS
6) Coagulopathy identified
7) Failed medical treatment (after at least 3 months pill or 6 months Mirena)
8) Patient wishes for surgery (ablation / hysterectomy)
Who does NICE define as a high risk patient when presenting with AUB?
Those women that either:
- are >45
- have declined or failed medical / conservative treatment
- pathology is suspected based on history / clinical exam
The above should be referred to secondary care.
Appropriate initial Tx of woman with AUB <45 with no history/examination findings consistent with structural pathology?
3-6 month trial of medical therapy - ECLIPSE trial showed that outcomes / satisfaction was higher amongst those treated with Mirena coil compared with TXA/NSAIDS/progesterone only pill/COCP
How should symptomatic bacteruria be treated in pregnant women?
If symptomatic of UTI, test with dipstick - if evidence of infection send for culture + start on empirical Tx for. 7 days: 1st line = Nitrofurantoin (avoid near term due to risk of neonatal haemolysis). 2nd line = Amoxicillin or Cefalexin
AVOID TRIMETHOPRIM IN PREGNANCY, TERATOGENIC IN 1ST TRIMESTER
How should Asymptomatic bacteruria be treated in pregnant women?
All women should be screened for asymptomatic bacteruria at booking - if culture is positive start on 7 days Nitrofurantoin / Amoxicillin / Cefalexin. REPEAT CULTURE AFTER TREATMENT TO ENSURE CLEARED.
Why is asymptomatic bacteruria treated in pregnant women but not the non-pregnant population?
Because of the increased risk of progression to pyelonephritis
What is the 1st line treatment for pyelonephritis in pregnancy?
A broad spectrum cephalosporin eg cefuroxime.
(also 1st line in the non-pregnant population! )
