Obstetrics Flashcards

Question 1

Q

Pre-eclampsia background

Answer

A

Epidemiology

approximately 5% of pregnancies
in approx 0.5% of cases
> eclampsia
> maternal death

Aetiology

unknown
risk factors
> previous hx
> family hx
> primip
> multiple pregnancy
> older age
> obesity
> HTN
> diabetes
> renal disease
> autoimmune disease

Pathophys

normal pregnancy
> invasion of trophoblastic cells into spiral arteries
> remodelling into large capacitance vessels
pre-eclampsia
> trophoblastic cells invade endo but not myometrium
> normal spiral artery remodelling does not occur
> placental hypoperfusion, hypoxia, ischaemia
> release of antiangiogenic factors into maternal circulation
> alters systemic endothelial function
> vasoconstriction and increased permeability

Question 2

Q

Pre-eclampsia evaluation

Answer

A

Hx

Timing
> most commonly after 34 weeks
> almost always after 20 weeks
> occasionally during labour or postpartum
May be asymptomatic
Severe symptoms screen
> altered mental status
> severe, persistent headache
> severe, persistant RUQ/epigastric pain
> photopsia/scotoma/blurred vision
> new dyspnoea/orthopnoea
Fetal wellbeing
> fetal movements
> abruption (abdo pain/contractions/PV bleeding)
Obstetric hx
> previous pregnancies/complications/HTN
> GA/route of delivery
Medical hx
> chronic illnesses?
> HTN/CVD
> kidney disease
> diabetes
Allergies
Medications
Social
> smoking/drinking/drugs

Exam

Height/weight/BMI
HTN
> 2 readings 4 hours apart
Hyper-reflexia or clonus
> indicates severe disease
Oedema
> pulmonary
> peripheral
Fundoscopy
> rarely abnormal (would imply underlying HTN)
> arteriolar narrowing/cotton wool/flame haemorrhages
Abdo palpation
> assess lie/presentation for pre-term delivery
Fundal height
> reduced = raised concern for IUGR (30% incidence)
Doppler
> FHR

Investigations

urinalysis
> protein 2+ on dipstick
> UACR >30
FBC
> anaemia?
> thrombocytopaenia?
EUC
> raised creatinine?
LFTs
> raised transaminases?
Consider
> coags if thrombocytopaenic
> CXR if concern for pulmonary oedema

Fetal wellbeing

Initial assessment
> growth scan
> BPP (NST/tone/movement/breathing/AFI)
> umbilical artery doppler (reduced end diastolic flow)
Ongoing monitoring
> umbilical dopplers most useful
> growth scans can be repeated in 2 weeks for velocity

Pre-eclampsia criteria

HTN plus
> proteinuria or
> end organ dysfunction
> growth restriction

Severe pre-eclampsia criteria

SBP >160 or DBP>110
CNS symptoms
> visual disturbance
> severe headache
Liver involvement
> transaminase >2x upper limit
> severe RUQ pain
Renal involvement
> creatinine >2x upper limit
Thrombocytopaenia
> less than 100,000/microL
Pulmonary oedema
HELLP syndrome
> severe subtype of pre-eclampsia
> haemolytic anaemia
> elevated Liver enzymes
> low Platelets

Question 3

Q

Severe pre-eclampsia management

Answer

A

Prelabour

Strictly inpatient management
> labour/delivery unit (consider tertiary transfer if ex pre)
> regular (4x daily) BP monitoring
> accurate fluid monitoring
> repeat blood tests daily (on advice)
> fetal wellbeing (dopplers and CTG)
Indication for delivery
> certainly for >34wks
> probably for >24wks (consider tertiary transfer)
Route
> no clear evidence for absolute caesarian need
> consider parity/GA/severity etc
Magnesium sulfate IV
> approx 4g IV then 1g/hr infusion (diluted)
> given immediately prophylactically
Anti hypertensives
> labetalol IV (start at 20mg and work up)
> hydralazine IV
> caution nifidepine
Anaesthetic review
> neuraxial = haematoma (platelets)/hypotension
> general = hypotension/hypertensive extubation/laryngeal oedema
> morphine = cardiorespiratory depression
Corticosteroids
> delay delivery by 48hrs if possible for full course
> betamethasone favoured
> clear benefit for <34 wks/ likely benefit <37 wks
Thrombocytopaenia
> transfusion usually only given if severe or bleeding

Intrapartum

Monitoring
> maternal HR/BP/RR/O2
> accurate fluid balance/consider maintenance fluids
Maintain antihypertensive therapy
Fetal wellbeing
> neonatologist/paediatrician attending
> continuous FHR
> glucose and cord gases

Postpartum

Magnesium sulftate
> no clear evidence for safe duration
> usually up to 48 hrs
> regular monitoring for SE
Bloods
> daily monitoring until repeatedly normal
Blood pressure
> often peaks in first week postpartum
> may last several weeks
> continue treating/swap to oral when non severe
Fluids
> risk of overload and pulmonary oedema
> restrict until passing urine freely

Question 4

Q

aneuploidy screening

Answer

A

Discuss

patient hx
> concerns
> family hx
> risk factors
genetic conditions
> information on common genetic conditions
> risks for pregnancy, baby and beyond
> concept of phenotypic variability
genetic testing
> description of available tests
> benefits and limitations of different tests
> screening vs diagnosis
> risk of unexpected findings without solutions
> private costs
implications
> continue or terminate pregnancy
> palliate baby with terminal illness
> timing and restriction of abortion methods
supports and further information
> referral to genetic counselling
> written information
> support groups

Combined first trimester screening

Timing
> 11-13+6 weeks
Components
> NT = >95th centile
> PAPP-A = low
> b HCG = high
> maternal age
> gestational age
Cost = approx $100
Conditions tested (66% of all aneuploidies)
> trisomy 21 (Down)
> trisomy 13 (Patau)
> trisomy 18 (Edwards)
Performance for 21
> sensitivity = 85%
> FPR = 5%
Soft markers increase sensitivity/specificity
> nasal bone/DV waveform/tricuspid flow
Confounders
> maternal weight
> smoking
> IVF
Report of results
> risk of disease

Cell free DNA

Timing
> from 10 weeks
> consider as secondary screen
Components
> maternal serum taken
> fetal fraction and number of sequence specific chromosomes = presence of aneuploidy
Offer early anatomy US @ 11-13 weeks
Conditions screened
> autosomal trisomies (21/13/18)
> sex chromosome aneuploidies
> micro deletions (diGeorge) not recommended
Unable to provide a result in approx 5%
> early GA
> suboptimal collection
> low FF in obese mothers/fetal karyotype/IVF
Private cost approx $400
Trisomy 21 performance
> sensitivity = 99%
> PPV = 90%
Causes of inaccuracies
> placental mosaicism
> maternal mosaicism
> vanishing twin
> copy number variants
> maternal cancer
Report of results
> positive/negative
> high risk/low risk

Second trimester testing

maternal serum screening (PPV = 3%)
> at 15-20 weeks
> maternal age
> AFP
> b HCG
> UE3
> Inhibin
cfDNA (from 10 weeks)

Question 5

Q

aneuploidy diagnostic tests

Answer

A

Indications

> patient preference (before screening)
> postive genetic screen

Relative contraindication

> alloimmunisation
> HIV
> Hep B/C

Amniocentesis

timing
> from 15 weeks gestation
> before = high risk adverse outcomes
procedure
> withdraw amniotic fluid using needle
> ultrasound guidance
post procedure care
> uterine cramping normal
> spotting/amniotic fluid leak immediately after
risks
> rupture of membranes
> indirect fetal injury (talipes/respiratory)
> direct fetal injury (rare)
> fetal loss = 0.5% (1/200)
> infection (rare)

Chorionic villus sampling

timing
> from 11 weeks
> before = high risk complications
procedure
> tertiary institute
> ultrasound guided
> transabdominal/transcervical approach
> placental tissue aspirated into syringe
> mild pain
post procedure care
> no exercise or sex 24hrs
> some light spotting is normal
risks
> fetal loss approx 1% (1/100)
> transverse limb reduction defects
> sampling failure
> vaginal bleeding
> infection (rare)

Assessment of sample

extremely low false negative rate
> variants of unknown significance in 5%
methods
conventional karyotyping
FISH
chromosomal microarray

Question 6

Q

diabetes pregnancy background and complications

Answer

A

Epidemiology

GD = approx 10% pregnancies
pre-existing = 2% pregnancies

Aetiology

pre-existing
GD risk factors
> older age
> personal hx
> family hx
> obesity
> physical inactivity
> high GI/low fibre diet
> smoking
> PCOS

Pathophys GD

relative insulin resistance normal part of pregnancy
> ensures adequate glucose delivery to fetus
> most marked resistance in 3rd trimester
diabetogenic hormones released by placenta
> growth hormone
> prolactin
> lactogen
> progesterone
GD develops when maternal beta cells are overwhelmed

Shared complications

short term
> LGA = preterm/caesarian/instrumental/dystocia/injury
> polyhydramnios = BPD/preterm/malposition
> pre-eclampsia
> neonate = hypoglycaemia/jaundice/CMP/cardiac/resp
long term
> increased risk of T2DM
> child = obesity/metabolic syndrome/diabetes

Pre-existing complications

Congenital defects
> 2-4%x base (incidence apex 5%)
> CCHD/neural tube defects
IUGR
Pre-eclampsia/HTN
Miscarriage
Aggravates underlying micro/macrovascular disease
DKA more common
> occurs at higher BGL
> more lethal for mother (fetal demise also common)

Question 7

Q

diabetes pregnancy evaluations and non BGL management

Answer

A

Screening

first antenatal visit
> all women
> low risk GD = BGL/high risk GD = GTT
> pre-existing = HbA1c/UACR/GFR/TSH/fundoscopy
24-28wks
> all women GTT

Diagnosis

GTT
> NBM for 8hrs prior
> fasting glucose
> 75g glucose
> glucose at 1 hr
> glucose at 2hrs
GDM criteria
> fasting = >5.1
> 1hr = >10.0
> 2hr = >8.5
pre-existing diabetes
> if diagnostic criteria met <1st trimester

1st trimester

Pre-existing
> cease ACEI/ARB
> low dose aspirin after 12wks
> higher folic acid supplementation

2nd trimester
-morph/neural tube scan at 20wks

3rd trimester

GD and good control/lifestyle only
> fetal movements may be sufficient
> growth scans close to term
Poor control/pre-existing
> NST/ST/BPP from 32 wks
> serial growth scans from 32 wks
> increase insulin if steroids given

Labour

Timing
> consider induction after 39/before 40wks
Route
> consider delivery at term for macrosomia
> consider caesarian for macrosomia >4.5kg
Intrapartum
> maternal glucose monitoring (fetal hypoglycaemia)
> continuous FHR
Post partum
> neonatal glucose monitoring
> loss of insulin resistance with placental delivery
> monitor glucose for 24-72hrs (unrecognised T2DM)

Question 8

Q

diabetes pregnancy BGL management

Answer

A

Diet

referral to dietician
> caloric needs individualised
> determined by baseline and GA
best evidence for low GI diet (vs low carb/calorie restricted)
> less insulin requirements
> lower birth weights
some evidence for increasing folic acid supplementation

Exercise

moderate intensity exercise
> increased muscle mass = increased insulin sensitivity
> lower blood glucose levels
> less insulin requirements

Insulin therapy

after lifestyle trial for 2-4wks
trial intermediate acting basal insulin at bedtime
> approx 6 units
assess fasting BGL over week
> more than 3 > 5 = increase by 2 units
> more than 3 > 6 = increase by 4 units
> more than 3 > 8 = increase by 6 units
avoid prolonged fasting at night
> paradoxically raises morning fasting levels
consider adding pre-prandial rapid acting bolus
> split approx 50% of total daily dose across meals

Glucose self monitoring

4x daily
> fasting/waking
> post prandial (1-2hrs)
log in book

Glucose targets

fasting <5.3
1hr post prandial <7.8
2hr post prandial <6.7

Question 9

Q

ectopic pregnancy background

Answer

A

Epidemiology

approx 1% of all pregnancies
up to 15% of first trimester bleeding

Aetiology

risk factors (ASEPTIC)
> age (older)
> smoking
> ectopic pregnancy in previous pregnancy
> PID
> tubal abnormalities
> infertility and IVF
> contraception failure (IUD/COP)

Pathophys

anatomic sites
> fallopian tubes (more than 95%)
> ovarian
> interstitial
> abdominal
> cervical
> hysterectomy scar
> intramural
> heterotopic

Question 10

Q

Ectopic pregnancy evaluation

Answer

A

Hx

Onset of symptoms usually after 8 weeks gestation
Vaginal bleeding
Lower abdo pain
> sharp or dull (not crampy)
> diffuse or localised
Rupture
> acute severe pain
> severe bleeding
> syncope
> shoulder tip pain
> tenesmus = blood in pouch of douglas
Pregnancy risk
> LMP
> hx unprotected sex/known pregnancy
> pregnancy symptoms (fatigue/mastalgia/nausea)
Obstetric hx
> previous pregnancies
> previous ectopics/miscarriages
Menstrual hx
> regularity
> intermenstrual/menorrhagia
Gynae
> contraception
> STI/PID
Social
> smoking

Review medical fitness

> lung/liver/kidney/peptic ulcer disease
> allergies (methotrexate)
> medications (immunosuppression/folate supplement)

Review surgical fitness
->previous operations (sites/complications/bleeding)

Exam

Often unremarkable
Vitals
> assess for shock (cap refill/warmth/colour/JVP)
> BP/postural hypotension
Abdo
> tenderness?
> acute abdomen in rupture
Speculum
> source of bleeding
Pelvic
> adnexal mass/tenderness
> cervical motion tenderness with rupture

Investigations

Unstable
> FAST scan for intraperitoneal haemorrhage
Quantitative b HCG
> confirms pregnancy
> provides level
Blood group and antibodies
> hold if significant bleeding
> sensitising event (anti D)
FBC
> anaemia due to haemorrhage
> baseline for methotrexate
EUCs and LFTs
> methotrexate baseline
Transvaginal ultrasound

Transvaginal ultrasound

Confirms ectopic
> gestational sac with yolk sac/embryo at ectopic site
> adnexal mass/empty uterus/free fluid
Suggests ectopic
> pseudosac
> complex extra ovarian adnexal mass
> tubal donut sign
> adnexa ring of fire sign on doppler
> consider heterotopic
Suggests rupture
> fluid in morrisons or douglas’ pouch
Absence of findings
> follow PUL protocol

Question 11

Q

medical management ectopic

Answer

A

Indications

> patient preference
> stable
> b HCG <5000
> no cardiac tones / ectopic mass <3-4cm

Contraindications

> unstable
> evidence of threatened rupture
> viable IUP/heterotopic
> liver/renal/pulmonary disease
> immunosuppression or peptic ulcers
> abnormal FBC, EUCs, LFTs
> breastfeeding

Risks

approx 1/3 experience side effects
> nausea/vomiting
> stomatitis/rash/itch/urticaria
> photosensitivity
rarely
> transaminitis/nephrotoxicity/myelosuppression
treatment failure approx 20%

Benefits

> avoids surgical complications
> similar efficacy to surgery when adequate doses given
> similar fertility outcomes to surgery
> similar risk as surgery of further ectopic pregnancies

Procedure
-IM single dose

Monitoring

b HCG on days 4 and 7
b HCG weekly until 0
inadequate decrease
> repeat dose (no more than three total)

Advice

> avoid conception for 4 months
> avoid folic acid supplements and NSAIDs
> avoid sunlight
> mild pain at 1 week is common
> severe pain needs to be investigated

Question 12

Q

surgical management ectopic

Answer

A

Indications

any b HCG level
unstable
rupture or impending rupture
heterotopic ectopic
methotrexate contraindications
methotrexate failure

Contraindications
-no absolute

Risks

surgical and anaesthetic risks
> haemorrhage
> infection
> damage to bowel or bladder
> adhesions/hernias
> nausea/vomiting post op
fertility
> vast majority will achieve conception if they try
retained ectopic tissue
> need for methotrexate therapy

Procedure

salpingectomy vs salpingostomy
> similar rate of future fertility
> salpingostomy = higher rate of retained/future ectopics
laparoscopic vs laparotomy
> laparoscopic preferred
> laparoscopic = less blood loss, faster operation, recovery and discharge
> consider laparotomy for interstitial or unstable

Follow up

> regular GP to follow up with?
Salpingostomy
> weekly b HCG until negative
> insufficient b HCG decrease = methotrexate
Salpingectomy
> post op B HCG unnecessary if histopath confirmed
Future conception
> no solid data
> 0-3 months common

Question 13

Q

expectant management ectopic

Answer

A

Indications

asymptomatic
no TVU findings of ectopic pregnancy
low (<1500) and decreasing b HCG
aware of risks
access to emergency treatment and close follow up

Contraindications
-any of indications absent

Risks
-rupture can occur with low and falling b HCG

Benefits

similar success rate (80%) to medical management
similar treatment time as medical management

Procedure

b HCG every 48hrs for 7 days
> then weekly until negative
abandon expectant management if
> any symptoms
> b HCG not decreasing
avoid conception until sonographic resolution

Question 14

Q

Miscarriage (<20 wks) background

Answer

A

Epidemiology

early pregnancy loss (first trimester)
> 10% clinically recognisable pregnancies
early second trimester loss (<20 weeks)
> less than 1% of pregnancies
almost half of parous women have EPL

Risk factors (ADIPOSE)

Age
> maternal
> possible paternal
Diabetes
> euglycaemia risk is baseline
Infection
> CMV
> syphilis
> parvovirus B19
Previous miscarriage
> OR for 1 = 1.5
> OR for 2 = 2.2
Obesity
Substances
> medications
> alcohol, smoking, cocaine
Exposures
> lead/arsenic
> air pollution
> radiation

Aetiologies

chromosomal abnormalities
> approx 3/4 of miscarriages
uterine abnormalities
> ashermans syndrome
> fibroids
> polyps
direct trauma
> violent
> iatrogenic (chorionic villus sampling)

Question 15

Q

miscarriage evaluation

Answer

A

Hx

confirm pregnancy
> LMP
> pregnancy test results
bleeding
> clots
> tissue
pain
> cramping
> shoulder tip
loss of pregnancy symptoms
syncope
> hypovolaemia
infection
> fever
> purulent discharge
obstetric hx
> previous pregnancies
> previous miscarriages
> assisted conception
gynaecological hx
> surgeries
> significant conditions
previous investigations
> US
> b HCG

Exam

vitals
> fever/tachycardia/hypotension = infection
> tachycardia/hypotension = hypovolaemia
> bradycardia/hypotension = tissue in cervical canal
abdo
> tenderness/guarding
> distension
> enlarged uterus
speculum
> bleeding from cervix
> open os
> tissue in cervical canal
bimanual
> cervical motion tenderness
> uterine tenderness in infection
> adnexal mass

Investigations

b HCG
> urine
> serum
FBC
blood group and antibodies
> transfusion
> sensitising event
Coags
Consider
> MSU
> STD
Initial transvaginal ultrasound
> IUP
> ectopic pregnancy
> absence of findings (PUL/complete miscarriage)
> GTD

Question 16

Q

suspected miscarriage investigation pathway

Answer

A

Intrauterine pregnancy

Confirmation
> yolk sac/embryo within gestational sac in endometrial cavity
Viable
> fetal heart present
Non viable incomplete miscarriage
> loss of cardiac tones in confirmed intrauterine
> MSD >25mm, no yolk sac/embryo
> CRL >7mm w no cardiac tones
Viability cannot be assess (MSD <25mm)
> repeat TVU when MSD expected to be 25mm
> assume MSD grows 1mm/day

Ectopic

Confirmed
> gestational sac with yolk sac/embryo at ectopic site
> adnexal mass/empty uterus/free fluid
> consider heterotopic
Likely
> pseudosac
> complex extra ovarian adnexal mass
> tubal donut sign
> adnexa ring of fire sign on doppler

PUL

DDx
> early IUP/non viable IUP
> ectopic
b HCG >3500 w. no findings
> almost certainly ectopic
> proceed with treatment
b HCG >2000 w. no findings
> ectopic/multiple gestation
> consider serum progesterone (low = non viable)
> expectant treatment as ectopic justifiable
> consider repeat TVU in 3 days (MSD visible at 3mm )
b HCG <2000 w. no findings
> repeat b HCGs over 48 hrs
serial b HCGs
> doubled = probably viable
> falling = likely unviable (including aborted ectopic)
> suboptimal rise (determined by initial level ) = ectopic or non viable IUP

Question 17

Q

Miscarriage general management

Answer

A

Breaking bad news

setting
> as soon as possible
> ideally both parents present
> offer and facilitate presence of support person
> minimise waiting times
> private, preferably away from maternity wards
principles
> provide as much information as possible
> don’t speculate
> talk about ‘baby’ or use name if given

Counselling

principles
> allow time for questions, grief and discussion
> discuss potential experience of grief/depression
memories
> offer to provide momento (eg. US picture)
> offer to see baby (prepare them for image)
supports
> discuss personal supports
> mental health services
> medicare pregnancy support counselling services
consider
> risk factors for psychological morbidity
> suicide risk (leading cause of maternal mortality)

Disposal of fetal tissue

if state requirements for birth registration met
> death certificate
> cremation or burial
birth registration requirements not met
> early pregnancy loss certificate can be provided
> hospital cremation
> private funeral director
> burial on private property

Histopath

products of conception sent to laboratory
> confirm pregnancy
> exclude ectopic
> exclude GTD
collection
> during surgery/inpatient miscarriage
> provide labelled specimen jar if expectant at home

Safety net

seek emergency assistance
> severe pain
> shoulder tip pain
> soaking more than 1 pad every hour
> syncope
> fever
return of period
> resolution of complications/completion of care
ongoing bleeds (>2 weeks)
> incomplete delivery
> GTD

Question 18

Q

expectant management miscarriage

Answer

A

Indications

> patient preference
> incomplete miscarriage

Contraindications

> later than first trimester
> unstable
> evidence of infection
> high risk of haemorrhage or coagulopathy
> suspected GTD

Risks

> 20% unsuccessful
> prolonged bleeding
> high rate of unplanned admission
> low and comparable infection rate (2-3%)
> 2% risk of transfusion

Benefit

> similar success rate as medical management
> avoid medication/surgery
> managed at home

Follow up with GP/EPAS

> repeat b HCG in a week
> US if b HCG decrease <90%

Question 19

Q

medical management miscarriage

Answer

A

Indications

> patient preference
> incomplete miscarriage

Contraindications

> later than first trimester
> unstable
> evidence of infection
> high risk of haemorrhage or coagulopathy
> prostaglandin allergy

Risks

> heavier and prolonged bleeding than surgical
> 20% unsuccessful
> low and comparable infection rate (2-3%)
> 1% risk of transfusion

Benefits
->faster process than expectant

Procedure

> outpatient/day procedure
> misoprostol per vagina single dose
> analgesia and anti-emetics

Expect

> bleeding within 24 hrs
> bleeding heavier than menses
> cramping pain
> pain and bleeding gradual get worse
> peaks for 2-4 hours
> occasional bleeding/dull ache/cramping for 2 weeks
> SE = diarrhoea and vomitting

Follow up with EPAS

> b HCG day 1 and 8 (confirm levels falling)
> US if b HCG decrease <90%
> repeat dose after 2-7 days if no response

Question 20

Q

surgical management miscarriage

Answer

A

Indication

first/early second trimester
patient preference
unstable/severe haemorrhage
evidence of infection
suspected GTD
unsuccessful medical/expectant management

Contraindication
-no absolute

Risks

standard procedure/anaesthesia risks
low and comparable infection rate (2-3%)
complications 1-2%

Benefits

shorter time to completion
lower rate unplanned hospital admissions
lowest rate of blood transfusion

Procedure

misoprostol PV 4hrs pre op
dilation and curettage (suction recommended)
general anaesthetic in OR

Follow up

GP if ongoing concerns
no b HCG or US

Question 21

Q

Initial antenatal visit

Answer

A

Hx

obstetric Hx
edinburgh post natal depression scale
genetic counselling
> aneuploidy screening
> carrier screening

Advice

lifestyle
> smoking, drinking, drugs
> diet and supplements
> exercise
> general restrictions
infection prevention
> immunisation
> precautions
ongoing care
> care team
> frequency of visits
> antenatal education courses available

Exam

height, weight, BMI
BP
Uterine
> size
> consistency
> position

Ultrasound

confirm
> pregnancy
> number
> location
> cardiac tones
GA
morphological anomalies
> poor sensitivity

Bloods

FBC
> haemoglobin (anaemia)
> MCV (thalassaemia/iron deficiency)
> platelets (thrombocytopenia)
Blood group and antibodies
MSU
> dipstick for proteinuria
> midstream culture
Diabetes screening
> random glucose
> HbA1c if high risk
Rubella
> antibody titre
Varicella
> documented previous chickenpox/shingles
> previous vaccination
Syphilis
> trepanemal assay
Chlamydia/gonorrhoea
> high risk
> under 25
HIV
> EIA + western blot
HBV
> HBVsAg
HCV total antibodies

Cervical screening
-if due

Question 22

Q

determining GA

Answer

A

Best estimates

US is best estimate of EDD if
> before 22 weeks
> discrepancy with LMP larger than expected for GA
most accurate estimate of EDD overall
> CRL during first trimester
accepted/unchanged EDD
> earliest sonographic assessment made

Ultrasound

indications
> offered to all before 22 weeks
> irregular periods
> LMP unknown
> conception with hormonal contraception
> uterine size differs from LMP
technique
> TVU preferred during first trimester
> TAU for remainder
limitations
> multiple gestation
> morphology abnormalities
initial scan in first trimester
> use CRL
initial scan in second/third trimester
> BPD, HC, AC, FL

Clinical assessment

Naegele’s rule
> minus 3 months + 7 days
> assumes 28 day period with fertilisation on 14th
Uterine size (archaic)
> 8 = plum/10 = orange/12 = grapefruit
> above symphysis at 12/at umbilicus at 20
> cm above umbilicus after 20
> invalid with fibroids, obesity, twins, retroverted

Question 23

Q

Diet and supplements advice

Answer

A

Diet

opportunity for intervention
> importance of well balanced diet
> referral to dietician/written information
caloric intake
> no need for increase in first trimester
> increase is only small in second/third trimester
> eating for two is misnomer
avoid
> raw/smoked meats/fish (listeria/toxoplasmosis)
> soft cheeses/pate (listeria)
> unpasteurised milk/cheese (brucellosis)
> large predatory fish (mercury)
> high caffeine intake
> sugar sweetened beverages (childhood obesity)
> artificial sweeteners appear safe
vegetarian
> balanced diet probably ok
> supplement vitamin D/E and iron
vegan
> also deficient in calcium, B12, omega 3 fatty acids
low carbohydrate
> deficient in folate

Supplements

multivitamin
> may not be needed in well nourished mothers
> prudent to presribe empirically
goals
> iron 30mg
> calcium 1000mg
> vitamin D 600IU
> folic acid 0.4-0.8mg (increase with gestation)
iodine
> adequate intake avoids hypothyroidism
> 250mcg recommended
> may be replete is consuming fortified foods (eg salt)
> excess intake can cause fetal goiter
vitamin A
> main concern is excess intake (teratogenic)
> avoid supplements containing >1500mcg

Question 24

Q

lifestyle advice

Answer

A

Substance use

Alcohol
> FASD = neurodevelopmental/ID/craniofacial
> possibly preterm/LBW/IUGR
> consider withdrawal and thiamine
Smoking
> approx 1.5 x miscarriage/still birth/SIDs
> approx 3x PPROM/preterm/LBW/abruption
Cannabis
> approx 3x perinatal morbidity/mortality
> risk of preterm/low birth weight
> long term neurodevelopment delay/ADHD
Amphetamines
> approx 3x fetal/neonatal death and preterm
> many other obstetric complications
Cocaine
> approx 3x preterm and LBW
> placental abruption
Opioid
> broad range of obstetric/neonatal complications
> heroin = Rh/HIV/IE/Hep B/C risk
> methadone substitution recommended

Exercise

standard exercise prescription
> controls gestational weight gain
> less lower back pain
> potential reduction pre-eclampsia/GD
small risk
> trauma leading to abruption
caution
> high intensity for long duration
> high level in IUGR/threatened pre term

Infection control

Influenza vaccine
> at any stage if during winter
DPT booster
> in third trimester
STDs
> advise barrier method if high risk
CMV and parvovirus
> good hand hygiene
> caution around children
Varicella
> pre conception vaccination
> IvIg available if unvaccinated exposure

Question 25

Q

FHR monitoring findings

Answer

A

Normal baseline
> 110-160
Baseline bradycardia
> hypothermia/oxaemia/glycaemia/thyroidism
> heart block
Baseline tachycardia
> infection/maternal fever
> hyperthyroid
> anaemia
> catecholamines
> arrhythmia
> hypoxaemia
HRV
> normal =5-25bpm
> presence of normal variability is reassuring
> absence/reduced is poor predictor of acidaemia/hypoxia
Accelerations (>+15 for 15s)
> presence is reasurring
> absence is poor predictor of acidaemia/hypoxia
Early decelerations (normal response to fetal head compression
> with peak of uterine peak contractions
Late deceleration
> occur post peak uterine contraction
> fetal hypoxia due to constriction of uterine arteries
> insignificant when with good variability and accelerations
> recurrence with minimal variability/accelerations is bad
Variable decelerations
> due to cord compression
> initial compression of umbilical veins = increase FHR
> compression of umbilical artery follows = decrease FHR
> uterine relaxation = effects occur in reverse
> concerning, requires close attention
Prolonged deceleration (due to fetal hypoxia of any cause
> up to 2 mins = non reassuring
> more than 3 mins = abnormal
> more than 10 mins = new baseline (severe hypoxia)
Sinusoidal pattern
> 3-5 cycles/minute for 20 minutes with no variability
> severe hypoxia or fetal anaemia
> rare and very concerning

Question 26

Q

GBS overview

Answer

A

Epidemiology

10-20% colonisation of vagina/rectum
> neonatal colonisation rate = 40-50%
> early infection rate = 0.5-0.05%

Aetiology

Risk factors
> prematurity
> prolonged rupture of membranes (>18hrs)
> maternal fever
> heavy maternal colonisation
> low level maternal/fetal serotype specific Ig
> previous infant with early GBS disease
Neonatal infection
> intra-amniotic infection (with intact membranes)
> passage through birth canal
> contact with outside environment

Pathophys

early onset <24hrs
> sepsis (most common)
> pneumonia
> meningitis
late onset <90 days
> fever/bacteraemia (most common)
> meningitis
> septic arthritis/osteomyelitis
> cellulitis
mortality
> overall = 3%
> pre-term early = 30%
morbidity
> CP
> ID
> seizures
> hearing/vision loss

Screening

rectovaginal swap/culture for all women
> false negative approx 5%
timing
> general = 35-37wks
> high risk for preterm = 3-5wks prior to EDD
exceptions
> GBS bacteruria/previous infant GBS = empiric rx

Labour management

Intrapartum antibiotics
> IV penicillin G or ampicillin
> at least 4hrs prior to delivery
> reduces risk of early disease by 80%
> risk of late onset unchanged
Indication for intrapartum antibiotics
> GBS+/GBS bacteruria
> previous early GBS disease
> unknown status + preterm labour/PPROM/prolonged rupture of membranes/intrapartum maternal fever

Question 27

Q

Caesarian risks discussion

Answer

A

Compared to normal vaginal delivery

Positives
> delivery date known
> avoids post-term neonatal mortality increase
> avoids risk of emergency caesarian
> lower rate urinary and bowel incontinence
> lower rate pelvic organ prolapse/perineal tear
> lower rate HIE/birth injury/asphyxia
> less vertical transmission HIV/HSV
Negatives
> higher rate TTN/RDS (only if <39 weeks)
> higher neonatal mortality
> longer hospitalisation/recovery time
Same
maternal mortality rate
post partum sexual function
pain 4 months post partum

Complications (HOISTED)

Haemorrhage
> approx 1L
> less than 5% need transfusion
Obstructed bowel (ileus)
> 15%
Infection
> 2%
Surgical error (rare)
> bowel/bladder perforation
> laceration to baby
Thrombosis (stroke/MI/VTE)
> 3x vaginal delivery risk
> 0.25% for VTE
Endometritis
Death
> less than 0.1%

Anaesthetic risk

neuraxial
general

Long term risk

abnormal placentation
> placenta accreta/previa/abruption
adhesions
hernias
nerve pain around scar

VBAC

uterine rupture
> TOLAC = 0.5% (< if previous successful delivery)
> twice as high as risk with repeat caesar
outcome of rupture
> 1/3rd hysterectomy
> neonatal death <3%
neonatal
> mortality 2-3x higher with TOLAC (very low)
> resus 2x higher with TOLAC

Categories

1 = immediate threat to maternal/fetal life (30mins)
2 = compromise with no threat to life (1hr)
3 = earlier than planned without compromise
4 = maternal request
> possible if harm/benefit understood by patient

Timing of planned/maternal request

before 39 wks
> increased risk of blood transfusion
> higher rates RDS/TTN
> higher neonatal mortality
at 39 wks
> approx 10% will require emergency CD prior to 39wks
> emergency has 2x risk of complications
after 39 wks
> increase perinatal mortality
> macrosomia
> dysmaturity syndrome

Question 28

Q

IUGR background

Answer

A

Epidemiology
-approx 10% births

Aetiology

Fetal
> genetic abnormality
> TORCH infections
Placenta
> pre-eclampsia
> abruption
Maternal (ACHINGS)
> age (extremes of)
> CKD
> HTN
> Insulin resistance
> nutritional deficiency
> genetics (previous SGA or personally SGA)
> SLE
Exposures
> teratogenic meds
> alcohol/smoking/cocaine/heroin/marujuana

Pathophys

Foetal response to compromised nutrient supply
> redirect blood flow to brain/heart/adrenals
> reduces overall size/fat/BMD/glycogen stores
> reduces renal blood flow and oligohydramnios
> preserve brain growth
> accelerate lung maturation
> increased RBCs
> decrease
Symmetric
> proportional reduction of body components
> chromosomal or infection
> occurs early in gestation
Asymmetric (majority)
> weight/abdominal size reduced more than length/HC
> adaptation to pathological stressor
> occurs later in gestation

Question 29

Q

IUGR evaluation

Answer

A

Hx

PC
> unwell lately?
> headaches/vision changes
> loss of blood or fluid
> pain?
> fetal movements
This pregnancy
> any complications
> scans (morph + aneuploidy) + serology
Past obstetric
> G/P
> G/A and route
> small babies
> HTN/diabetes
Past medical
> any chronic illnesses
Allergies
Medications
Supplements and food avoidance
Social
> Smoking/drinking/drugs
> contact with children
> proximity for follow

Exam

Height/weight/BMI
BP
Abdo palp
Fundal height
Doppler

Confirm diagnosis with ultrasound

Urgent CTG
SGA
> weight below 10th centile in second trimester
> may be constitutional or restricted growth
> consider AC/AFI/growth velocity

Determine cause

Fetal survey
> doppler (umbilical/uterine/middle cerebral arteries)
> BPP
Anatomy scan
> if abnormal, consider cell free DNA for aneuploidy
> if negative, consider amniocentesis for microarray
Infection workup
> maternal CMV/rubella/varicella seropositivity

Question 30

Q

IUGR management

Answer

A

Monitoring

Usually monitored as outpatients
Weight
> review every 2 weeks if concerned
> consider velocity (normal in constitutional)
US doppler
> umbilical artery most useful
> review every 2 weeks if first two are normal
> review weekly if abnormal or concerned
> reduced/absent end-diastolic flow = consider delivery
BPP or NST with AFI
> not needed if mild
> twice weekly if severe
> daily if abnormal doppler

Delivery consideration

Issue
> pre term delivery has high mortality/morbidity
> each day in utero between 26-29wks increases survival up to 2%
> mortality in IUGR rises sharply at time (placental insufficiency)
GRIT trial
> randomised to immediate or delayed delivery
> when obstetrician was uncertain
> immediate group = fewer stillbirths/more neonatal deaths
> long term neurodevelopment outcome similar
DIGITAT trial
> randomised to spontaneous/expectant at term
> spontaneous had lower birth weight
> same adverse events/same caesarian rate/long term developmental outcomes
Consider
> dopplers/BPP/NST/risk factors
> gestational age
> patient preference
> need for caesarian delivery if poor dopplers
> corticosteroids and magnesium sulfate

Intrapartum

Issues
> intrapartum heart rate abnormalities
> birth asphyxia/HIE
> meconium aspiration
> polycythaemia
> hypothermia
> hypoglycaemia
Approach
> continuous fetal heart monitoring
> low threshold for emergency caesarian
> neontal support present
> umbilical blood gas and glucose at birth

Long term

catch up growth
CVD/diabetes/renal disease/neurodevelopment

Question 31

Q

Rh incompatibility overview

Answer

A

Epidemiology

Rh -ive
> 15% of caucasians
> 7% africans
incompatibility in 10% pregnancies

Aetiology

Rh -ive mother
Rh +ive baby
> inherited from father

Pathophys

sensitising event
> occurs in majority of pregnancies
> fetomaternal haemorrhage (most placental insults)
> passage of fetal cells across placenta
formation of maternal anti-D Ig
> formation of memory B lymphocytes
> future challenge leads to plasma cell Ig production
haemolytic disease of the new born
> maternal Ig cross placenta attache to fetal RBC
> RBCs sequestered in spleen and destroyed
> extramedullary haematopoeisis
> hepatosplenomegaly/pHTN/HF/cerebral hypoxia
> hydrops fetalis/intrauterine death

Screening for incompatibility

blood group, Rh status, antibodies
> first antenatal visit
> Rh -ive repeated at 24-28wks
> after any sensitising event

Diagnosing incompatibility

if mother Rh antibody +ive
> paternal blood group
Paternal zygosity if Rh +ive (PCR for RHD genes)
> if homozygous = fetus Rh +ive
> if heterozygous = 50% chance fetus Rh +ive
Amiocentesis (>15wks) or cfDNA (>10wks) if heterozygous

Monitoring incompatability

Baby Rh +ive
> serial (monthly) maternal indirect coombs
If antibody titre rises above critical threshold
> doppler MCA for severe anaemia ever 1-2wks
If suspected sensitising event
> rosette test = presence of fetal RBC in maternal blood

Sensitisation prevention

Rh incompatibility diagnosed
> maternal Ig present = no benefit of anti-D
> routine prophylaxis = anti-D at 28wks
> fetomaternal haemorrhage = anti-D
> sensitising procedure = anti-D 72hrs prior
> delivery = additional anti-D 72hrs prior
Dosage
> Kleihauer test/flow cytometry = %fetal RBC

Question 32

Q

Infertility background

Answer

A

Epidemiology

fecundability
> 85% over 12 months regular unprotected sex
> 25% in first 3 months, then decreases

Aetiology

Risk factors
> age >35
> obesity/low BMI
> smoking
> previous STD

Pathogenesis

Female factors (1/3rd)
> diminished ovarian reserve with age (majority)
> oligo/anovulation (PCOS/prolactin/hypogonadism/hypothalamus)
> tubal (post infection/endometriosis/pelvic adhesions)
> uterine (adhesions/mullerian abnormalities)
> smoking/obesity
Male factors (10%)
> oligo/azoospermia (majority idiopathic)
> primary/secondary hypogonadotrophinism
> congenital testicular disorder (klinefelter/cryptochordism)
> acquired testicular disorder (infection/drugs/exposure)
Combined factors (1/3rd)
Idiopathic 5%

Question 33

Q

Female factor internality evaluation

Answer

A

Hx

Menstrual hx
> regular menses/moliminal symptoms = ovulatory
> long = anovulation
> short = anovulation/endometrial dysfunction
Sexual hx
> timing and regularity
> dyspareunia (PID/endometriosis/adhesions/uterine abnormality)
Hypothalamus
> stress/weight loss/exercise
> anosmia
Pituitary
> headache/vision changes/nipple discharge
Ovaries
> acne/hirsuitism/overweight/irregular periods
> SLE/UC
Tubes
> pelvic surgery/STD
> endometriosis/pelvic pain/menorrhagia/dysmenorrhea
Uterus
> procedures/instrumentation
Social
> smoking
> alcohol and substances
> stress/mood/psychiatric disorders
> occupational exposure

Exam

height/weight/BMI
inspection
> hirsutism/acne
> galactorrhea
> secondary sex characteristics/syndromic features
pelvic
> abnormal shape uterus
> nodular pouch of douglas (endometriosis)
> adnexal mass/tenderness

Assess ovulation

serum progesterone
> 7 days before menses
> ovulation if high
urine LH sticks
> serial assessments at home
> predicts ovulation approx 24hrs in advance
serial ultrasounds
> usually restricted to during treatment
if anovulatory
> FSH/LH (hyper/hypogonadotrophic hypogonadism)
> androgens (PCOS)
> TSH
> prolactin
> karyotyping

Anatomical assessment

Imaging
> transvaginal ultrasound (uterine/tubal/ovarian morph)
> hysterosalpingography (uterine/tubal path)
> saline infusion sonography (uterine path)
> MRI (uterine path pre-op planning)
Surgical
> laparoscopy (endometriosis/adhesions) with chromotubation (tubal patency)
> hysteroscopy (uterine path)

Ovarian reserve testing

Basal FSH on day 3
> less than 2 = hypogonadotrophinism
> greater than 10 = possible reduced ovarian reserve
> greater than 30 = menopausal/ovulatory surge
Antral follicle count on day 3
> transvagianl ultrsound
> less than 4 indicates diminished reserve
AMH on any day
> less than 1 ng/mL indicates diminished reserve

Question 34

Q

infertility management

Answer

A

Non pharm

Diet
> limited evidence
> beneficial for future pregnancy
Weight loss
> high BMI or PCOS
Weight gain
> athlete/low BMI/anorexia
Reduce smoking/drinking/substances
Psychology support
> high stress associated with infertility
> stress/psychological morbidity risk factor for infertility

Ovarian stimulation

Clomiphene
> indicated for normogonodotrophic ovulatory dysfunction
> ineffective in hypogonadotrophic hypogonadism
Letrozole
> indicated for normogonadotrophic ovulatory dysfunction
Gonadotrophin therapy
> failed first line treatment
> hypogonadotrophic hypogonadism

Tubal abnormalities

IVF
> failed ovulation treatment
> tubal abnormality
> male infertility
> uterine abnormalities with surrogate
Tubal patency improving procedures
> distal occlusion may be treated/proximal should not
> fimbrioplasty (lysis of adhesions/dilation of strictures)
> neosalpingostomy (new tubal opening)

Uterine abnormalities

Setate
> some evidence for surgical intervention
Fibroids
> consider surgery if other treatments failed
> best evidence for submucosal
Polyps
> polypectomy for large endometrial polyps

Specific aetiologies

Endometriosis
> first line = IVF
> surgical ablation of impants/adhesiolysis
PCOS additional treatments
> ovarian stimulation
> metformin
> ovarian drilling
Hyperprolactinaemia
> bromocriptine

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Obstetrics Flashcards

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