Obstetrics Flashcards
What is the best way of estimating gestational age?
First trimester ultrasound at 12/40 weeks
Measuring the Crown Rump Length
Describe the pregnancy timeline:
Booking appointment 8-10 weeks Dating scan 11-13 weeks Anomaly scan 20 weeks OGTT at 24-28 weeks - if needed Anti-D prophylaxis 28 & 34 weeks - if negative
Describe the combined screening:
11 - 13 weeks - combines ultrasound and 2 blood test
- hCG
- PAPP-A (Pregnancy associated protein A)
Gives an early result and is 85% sensitive
2.2% Fasle positive
Describe the quadruple test:
14-20 weeks - uses 4 blood tests and maternal age - hCG - alpha-fetoprotein (AFP) - unconjugated oestriol - inhibin-A 80% sensitive and 3.5% false positive
Explain the risk and options for a mother who has screened positive for the combined screening test:
Risk - explain percentage chance
1st option is to do nothing
Chorionic Villus Sampling: 11 -14 weeks
- 1 -2% chance of miscarriage
Amniocentesis: 15 weeks and onwards
- 0.5-1% chance of miscarriage
Non-invasive prenatal testing
- Blood test, Currently private
Explain the risks of a breech presentation during delivery:
Cord prolapse
Difficulty delivering the head
Fetal hypoxia
Increased foetal mortality and morbidity
Explain External Cephalic version
A method for turning a breech into a head down
May prevent a breech vaginal delivery or c-section
Uterine relaxants given before hand e.g. Terbutaline
CTG performed before and after
May require Anti-D
Risk - of foetal distress, cord entanglement
- Emergency c-section 1:200
Success rate 40% in nulliparous, 60% in multip
What are the possible causes of large for dates?
Wrong dates
Big baby
Polyhydramnios
Big baby & Polyhydramnios
Causes of polyhdramnios:
DITCH
Diabetes Idiopathic Twins - twin to twin Congenital abnormalities - VSD etc. Heart failure - anaemia - haemolysis - causes increased naturitic peptides
Explain the risk of polyhydramnios:
Placental abruption Pretty unusual lie Premature labour Prolapse of cord Post partum haemorrhage Perinatal mortality
What are the four main indications for induction:
Post dates
Pre-labour rupture of membranes
Pre-eclampsia
Plus diabetes
What are the three stages of Induction of labour:
Stretch and sweep
- Cervical ripening - Vaginal prostagladins
- Amniotomy - ARM
- Cervical dilation - IV Oxytocin
Explain stage one of induction of labour:
Cervical ripening
- vaginal prostaglandin pessaries or gel
- Softens and shortens cervix
- Risk of hyperstimulation and fatal distress
- Intermittent CTG monitoring required
Explain stage two of induction of labour:
Amniotomy
- Once cervix is sufficiently effaced
- an amnihook is used to rupture the membranes
- Risk of cord prolapse if presenting part is high
What score is used to predict the likelihood of spontaneous labour?
Bishop score
Explain stage three of induction of labour:
Cervical dilatation
- IV oxytocin used to generate contractions
- Start on a low dose and titrate it up
- To achieve 3-4 contractions every 10 minutes
- Risk of uterine hyper stimulation
- Continuous CTG monitoring
- Progress is monitored on a partogram
What are the risk of diabetes in pregnancy?
SMASH
Shoulder dystocia Macrosomina Amniotic fluid excess Still birth Hypertension and neontal hypoglycaemia
What advice should be given to someone with pre existing diabetes who is wanting to get pregnant?
The impact of diabetes starts from pre-conception
Take high dose folic acid (5mg daily) from pre-conception
Don’t stop contraception until good control achieved
Avoid pregnancy if poor control
increases risk of congenital malformations
Monitor eyes and renal function before and during pregnancy
Council on the effects of pregnancy on pre-existing diabetes:
Insulin resistance increases in pregnancy
So increases insulin requirement
Acceleration of retinopathy
Deterioration in renal function if preexisting nephropathy
Risk of maternal hypoglycaemia in early pregnancy
Explain the principles of managing pre existing diabetes in pregnancy:
Pre-conception counselling - improve control
Manage with diabetes team
Stop ACEi and Statins
Screen for and monitor vascular complications
Explain the Oral Glucose Tolerance Test:
Used to screen high risk women for gestational diabetes
Performed between 24-28 weeks
Fasting venous plasma glucose measured
Given a drink containing 75g of glucose
Venous plasma glucose measured again at 2 hours
Fasting: >5.6 or 2 hour: >7.8 mmol/L
Who gets screened for gestational diabetes?
BMI >30 Previous gestational diabetes Previous big baby >4.5kg First degree relative with diabetes Ethnic groups - South Asia, Black, Arab
Previous unexplained still birth
Polyhydramnios
Large for dates in this pregnancy
PCOS
Can a woman take an ACEi during pregnancy?
No - ACE inhibitors are contraindicated during the second and third trimesters of pregnancy because of increased risk of fetal renal damage.
Can a woman take a statin during pregnancy?
Women wishing to become pregnant should stop use of statins three months prior to attempting to conceive, or as soon as pregnancy is confirmed, due to the theoretical risk of fetal abnormality
What is the stepwise management of gestational diabetes?
- Conservative: - Refer to dietician
- Exercise, walk for 30 mins after meals - Medical: Metformin 500mg daily with food
- Can increase dose after a week - Single injection intermediate acting insulin
- Add short acting insulin before meals
What is the obstetric management of pre existing and gestational diabetes?
Serial growth scans to predict macrosomnia
Plan for induction at 38-40 weeks
Be alert for possible shoulder dystocia
If already >4.5kg consider elective c-section
Close neonatal monitoring of blood sugars
What is the immediate management of shoulder dystocia
McRoberts manœuvre - flex and externally rotate the hips
Suprapubic pressure
Episiotomy - for access for advanced intervetions
What advanced interventions can be performed for shoulder dystocia when McRoberts and Suprapubic pressure fail?
Woodscrew manoeuvre
- Rotate the shoulder
- Deliver posterior arm
- Break clavicle
Zavanelli manoeuvre
- Emergency c-section
Explain gestational hypertension
BP >140/90 on more than one occasion
Onset after 20 weeks
15% risk of developing pre eclampsia
Explain Pre-eclampsia:
A disease of the placenta that starts after 20 weeks if the arteries fail to remodel themselves, making blood flow poor.
It causes high blood pressure, protein in the urine
and sometimes swelling of the hands, face and ankles.
It resolves within an few days of delivery but can lead to some serious complications for the mother and the baby.
What is the treatment for hypertension in pregnancy and what is the target BP?
Labetalol - 1st line, to reduce stroke risk
Nifedipine or Methyldopa - 2nd line
Target range <150 systolic
Over treatment can cause IUGR
What is used for the prevention of pre eclampsia in high risk patients?
Aspirin 75mg from 12 weeks
Who is at high risk of pre-eclamsia and should receive prophylactic aspirin 75mg from 12 weeks?
ECLAMP
Existing hypertension Chronic kidney disease Lupus (SLE) Antiphospholipid syndrome Maternal diabetes Previous pregnancy with hypertension
What are the maternal complications of pre-eclampsia?
SHAME
Stroke HELLP syndrome Abruption of placenta Multi organ failure +/- DIC +/- Death Eclampsia
What are the fatal complications of pre-eclampsia?
Foetal growth restriction
Intra-uterine death
Premature delivery - iatrogenic
What is HELLP syndrome?
Haemolysis
Eleveated Liver enzymes
Low Platelets
What are investigations should you perform when suspecting pre-eclampsia?
Bedside:
- BP 2 readings,
- Urine dip
Once confirmed - do pre-eclampsia bloods
FBC - low platelets
U&E - raised urea and creatinine
LFTs - raised AST
Low Hb and high bilirubin if haemolysis = HELLP
What 4 red flag symptoms predict eclampsia?
Headache
Visual disturbances
Epigastric or RUQ pain - hepatic capsule distension
Breathlessness - pulmonary oedema due to ARDS
What 3 red flag signs predict eclampsia?
Peri orbital oedema
Hyper-reflexia
Clonus
What is the emergency management of Eclampsia?
ABC
Turn patient onto left side
IV Magnesium sulphate
IV labetalol
How would you investigate suspected pre labour rupture of membranes?
Sterile speculum - looking for pooling of amniotic fluid
- Foetal fibronectin
- Amnisure - Placental alpha-microglobulin-1
Urine dip for infection
CTG
Bloods: FBC, U+Es, CRP
Management of pre labour rupture of membranes:
Admit for observations
Most will labour spontaneous within 24 hours
Offer induction at 24 hours
Management of pre term labour:
Betamethasone 12mg IM x 2 doses, 24h apart
Consider tocolytics
Consider transfer to tertiary unit
- Intrapartum antibiotics
Management of preterm prelabour rupture of membranes:
Admit for observation 80% chance of labour with 7 days Betamethasone 12mg IM x 2 doses, 24h apart Erythromycin 250mg QDS for 10 days Consider transfer to tertiary unit
What is the antenatal management twins?
Oral Iron, Folic acid 5mg, Aspirin 75 mg Detailed anatomy scan and cardiac scans Regular growth scans - DCDA 4 weekly (from 16 weeks) - MCDA 2 weekly (from 16 weeks) - MCMA Regular BP and urine checks
What is the obstetric management of twins?
Vaginal delivery if presenting twin cephalic
If breech then c-section
Aim to deliver at:
DCDA = 37-38 weeks
MCDA = 36 weeks
MCMA = 32-34 weeks by C-section regardless
How is the donor twin affected in twin-twin transfusion syndrome of monochorionic twins?
Anaemic
Growth restricted
Oligohydramnios
Hypotension
How is the recipient twin affected in twin-twin transfusion syndrome of monochorionic twins?
Polycythaemic Hypertensive Cardiac hypertrophy Oedema (hydrops) Polyhydraminios
What is defined as small for gestational age?
less that the 10th percentile for gestational age
What are the possible reasons a small for gestational age foetus?
SWAN
Starved small - IUGR
Wrong small - wrong dates
Abnormal small - Chromosomal, Infection
Normal smal - constitutional
Who is it high risk of IUGR?
SHIT
Smoking
Hypertension
IUGR previously
Twins
What will be seen on US of a foetus with IUGR?
Brain sparing effect of placental insufficiency
Abdominal circumference affected more than head
Increasing placental resistance
- Absent end diastolic flow
- Reversed end diastolic flow
Management of a foetus with absent or reversed end diastolic flow on US:
Intensive surveillance - CTG, USs
Consider early delivery
Steroids is < 34 weeks
Between what gestation ages are maternal steroids beneficial for a pre term neonate?
24 - 34 weeks
What defines an antepartum haemorrhage?
Bleeding in pregnancy after 24 weeks
Bleeding before 24 weeks is a threatened miscarriage
What are the possible causes of an antepartum haemorrhage?
Uterine: - Placental abruption - Placenta praevia - Vasa praevia - Marginal bleed (from the placental edge) Cervical: - 'Show', loss of mucus plug - Cervical polyp or ectropion - Cervical cancer Vaginal: - Trauma or infection
Painless, bright red vaginal bleeding in a pregnant woman suggest what?
Placenta praevia
Painful, vaginal bleeding with dark red blood in a pregnant woman suggest what?
Placental abruption
How do you investigate cause of antepartum haemorrhage?
Do NOT do a vaginal exam until after placental site has been confirmed by ultrasound
What is the immediate management of antenatal haemorrhage:
Call for help from seniors
ABC approach
15L non re-breath oxygen,
Tilt bed head down and put in left lateral position
2 large bore cannulae & give 500mls 0.9% saline
Send bloods for FBC, clotting screen, GXM 4 units blood
Urinary catheter
Check fetal condition - CTG
If necessary give O negative
Assess cause of bleeding - US
What is the immediate management of post partum haemorrhage:
Call for help - senior staff plus pairs of hands
ABC approach
15L non re-breath oxygen & tilt bed head down
2 large bore cannulae & give 500mls 0.9% saline
Send bloods for FBC, clotting screen, GXM 4 units blood
Urinary catheter
If necessary give O -ve blood +/- FFP and platelets
Assess cause of bleeding
What defines a primary post partum haemorrhage?
loss of > 500ml of blood within 24 hour of delivery
What defines a secondary post partum haemorrhage?
excessive bleeding from the genital tract between 24 hours and 6 weeks post-partum
What are the primary causes for post partum haemorrhage?
4 Ts of PPH
Tone - uterine atony
Tissue - retained placenta, prolonged third stage
Trauma - vaginal or cervical tear
Thrombin - pre-eclampsia or DIC
What are the risk factors for uterine atony?
Previous episode of PPH
Prolonged third stage
Multiple pregnancy
Fetal macrosomia
Polyhydramnios
What is the initial pharmacological management of post partum haemorrhage?
Ergometrine IV bolus
Syntocinon infusion
What is the stepwise surgical treatment for post partum haemorrhage ?
Evacuation of retained placenta Intrauterine balloon tamponade Haemostatic suture Internal iliac ligation Consider hysterectomy
When should Anti-D be given and why?
Routinely as 28 and 34 weeks or at a sensitising event
To prevent rhesus D alloimunisation in D negative women who may be carrying a D positive foetus
What are examples of a sensitising event that would require extra Anti-D?
Chorionic Villus Sampling Amniocentesis Termination of pregnancy Threatened or complete miscarriage after 12 weeks Antepartum haemorrhage External cephalic version Closed abdominal injury
