Antepartum Care Flashcards
Incidence of placenta praevia
1 in 200 pregnancies
Resolution rate of placenta praevia at 32 weeks
90%
Resolution rate of placenta praevia at 36 weeks
50%
Cervical length of less than ________ predicts antepartum haemorrhage and emergency c/s
31mm
Risk factors for placenta praevia
Smoking
ART
Caesarean birth
Timing of steroids for placenta praevia
34+0 to 35+6
Timing of delivery in placenta praevia
34+0 - 36+6 if vaginal bleeding/other risk factors
36+0 - 37+0 if uncomplicated
Risk of bleeding by gestation with placenta praevia
4.7% by 35 weeks
15% by 36 weeks
30% by 37 weeks
59% by 38 weeks
Risk of MOH requiring blood transfusion with placenta praevia c/s
12 x higher
Risk factors for PAS
C/S
Previous uterine surgery
Placenta praevia
IVF
Maternal age
Bicornuate uterus
Adenomyosis
Submucous fibroids
Myotonic dystrophy
Rate of PAS with praevia and 3 or more c/s
50-67%
Proportion of PAS undiagnosed
1/3 to 2/3rds
USS signs of PAS
Abnormal uterus-bladder interface
Abnormal vasculature on colour Doppler
Abnormal Placental lacunae vascularity
Increased vascularity of the placental bed
Loss of clear zone
Myometrial thinning
Placental bulge
Focal exophytic mass
Bridging vessels
MRI signs of PAS
Abnormal uterine bulging
Dark intraplacental bands
Heterogenous signal intensity in placenta
Disorganised vasculature of placenta
Disruption of uteroplacental zone
Gestation for delivery with PAS
35+0 to 36+0
Risk of urinary tract injury during PAS surgery
16% of uterus preserved
57% with standard hysterectomy
Risks of conservative management of PAS (placenta in situ)
Infection
Bleeding
Septic shock
Peritonitis
Uterine necrosis
Fistula
Pulmonary oedema
Acute renal failure
VTE
Injury to adjacent organs
Emergency cerclage can be considered up from ______ to _____ gestation
16+0 to 27+6
Risk of preterm birth with cervical length of <25mm and history of PTB
14%
Indications for serial cervical length scans
Previous PTB/2nd trimester loss 16-34 weeks
Previous PPROM <34 weeks
Previous cerclage
Intrauterine adhesions
Known uterine variant
History of trachelectomy
Indication for trans abdominal cerclage
Previous failed vaginal cerclage
Risks of cervical cerclage
Cervical laceration
Bladder injury
Membrane rupture
Fistula formation
Removal under anaesthetic required if performed with bladder mobilisation
Removal of cervical suture should be at
36+1 to 37+0 unless pt undergoing c/s
History indicated cerclage
Singleton, 3 or more preterm births
Singleton, history of second trimester loss
Gestation at which you MUST remove cervical cerclage after PPROM
Less than 23 weeks
More than 34 weeks
Incidence of PPROM
3%
PPROM occurs in what percentage of PTB
30-40%
Median latency after PPROM
7 days
Management of PPROM
Delivery if septic
Erythromycin (penicillin if allergic) 10 days or established labour
Offer steroids between 24+0 to 33+6
Consider steroids 34+0 to 35+6
Benefit of abx in PPROM
Reduce babies born within 48 hours and within 7 days
Reduce risk of chorio
Reduces risk of neonatal infection, surfactant use, oxygen therapy and abnormal cerebral USS
Most helpful marker of chorioamnionitis
CRP (77% specificity)
Tocolysis in PPROM is not recommended because
Associated with lower APGAR scores (<7) and increased need for ventilatory support
Increased risk of chorio below 34 weeks
Timing of Delivery following PPROM
37+0
From 34+0 if GBS pos
MgSO4 for PPROM
Offer when Planned or established labour 24+0 to 29+6
Consider between 30+0 and 33+6
Average time to delivery after PPROM
8-10 days at 24+0 to 28+0
5 days at 31+0
May be sooner if there is oligo
Factors leading to worse outcomes for PPROM
Oligo
Non-cephalic presentation
Occurring <26+0
Consider hospital care
Benefits of antenatal steroids
Reduce NND
Reduce NEC
Reduce RDS
Reduce intraventricular haemorrhage
Reduce risk of infection in first 48 hours of life
Reduces risk of ITU admission/respiratory support
Reduce developmental delay
Optimal Timing of steroids
Greatest benefit with delivery within 48 hours of first dose
Benefit seen within 24 hours of delivery
Benefit for up to 7 days of giving
Dose and type of steroids
Dexamethasone phosphate 12mg 24 hours apart or 4 doses of 6mg given 12 hourly (better risk reduction for IVH)
Betamethasone phosphate/acetate mix - 12mg 24 hours apart
Gestations to give steroids
Offer between 24+0 to 34+6
Consider 35+0 to 36+6
Consider between 22+0 to 23+6
Harms of steroids
Affects maternal glycaemic control for 5 days
Neonatal hypoglycaemia
Reduced birth weight with repeat courses
Neurodevelopmental affects if baby born at term
Stillbirth rate
32 in 10, 000 (white)
72 in 10, 000 (black)
51 in 10, 000 (Asian)
Consider Prophylactic vaginal progesterone when
History of PTB up to 34+0/2nd trimester loss OR cervical length is <25mm on TV USS
Offer either cerclage or vaginal progesterone when
History of PTB/2nd trimester loss AND cervical length <25mm
Gestation to give vaginal progesterone
Start between 16+0 and 24+0
Continue until 34+0
Offer prophylactic cerclage when
History of cervical trauma OR
History of PPROM
AND cervical length <25mm
Contraindications for emergency cerclage
Uterine contractions
Active vaginal bleeding
Signs of infection
Diagnosis of PTB at 30+0 or more
15mm cervical length on TV USS (preferred)
OR
Fetal fibronectin >50
Treat for PTB if above tests not available
Tocolysis should be given at what gestation?
Consider between 24+0 and 26+0
Offer PTB between 26+0 and 33+6
Tocolysis medication
Nifedipine
Oxytocin receptor antagonists if nifedipine is contraindicated (atosiban)
Do not use betamimetics
Monitoring of FH in established PTB
Offer IA or CTG if no other risk factors
Fetal scalp electrode monitoring should not be used below _____ gestation
34+0
FBS should not be used below ______ gestation
34+0
Cord clamping technique in preterm babies
60 seconds
Hold baby below the level of the placenta
Incidence of PTB
7.3% of live births
Gestation for amniocentesis
15+0
Higher risk of low DNA quantity prior to 16+0
Risks of amniocentesis
Miscarriage 0.5%
Second sample required 6%
Blood stained sample 0.8%
Maternal cell contamination 1-2%
Rapid test failure 2%
Failed cell culture 0.5-1%
Severe infection
Fetal injury
Maternal visceral injury
Risks of CVS
Miscarriage 0.5%
Second sample required 6%
Confined placental mosaicism 2%
Failed cell culture 0.5-1%
Severe infection
Fetal injury
Maternal visceral injury
Gestation for CVS
10+0 minimum
Ideally after 11+0 to reduce technical difficulty
Pregnancy loss risk for CVS/amniocentesis in multiple pregnancy
1%
Risk of cross contamination in multiple pregnancy CVS
1%
Risks of 3rd trimester amniocentesis
10% risk cell culture failure
PTB 3-4%
More than one needle insertion 5%
Blood stained sample 5-10%
Amniocentesis/CVS considerations with blood borne viruses
Testing required prior to test
Ensure HIB viral load is undetectable
Ensure Hep B viral load is <6.99log10 copies/ml
No evidence for Hep C
Maternal mortality rates
11.66 per 100, 000 (white)
Definition of early FGR
Onset before 32+0
Fetal size or AC <3rd centile OR absent EDF
OR
<10th centile with uterine artery >95th or UA PI >95th centile
Static growth definition
No forward growth velocity in AC or EFW measured 14 days apart
Definition of late FGR
> 32+0
AC/EFW <3rd centile
OR (2 of the following):
AC/EFW <10th centile
AC/EFW crossing 2 quartiles
Cerebroplacental ratio <5th centile or UA PI >95th centile
Definition of FGR in previous pregnancy
Previous baby <3rd centile
PET or FGR requiring birth <34+0
EFW <10th centile with evidence of placental dysfunction
Optimal time to start aspirin
11+0 to 16+6
Incidence of early onset FGR
0.3%
Timing of SFH measurement
First measurement between 26+0 and 28+6
No more than every 2 weeks, at each appointment
Method to determine EFW
Haddlock formula
Gestation for uterine artery Doppler
20+0 - 24+6
Fetal infection accounts for what percentage of SGA?
5%
Short femur length is associated with _____________
SGA and PTB
Early FGR coincides with maternal hypertension in ________ of cases
70%
Treatment for anaphylaxis
1:1000 adrenaline 500mcg IM (0.5ml)
Incidence of cardiac arrest in pregnancy
1 in 36000 pregnancies
Mortality rate of cardiac arrest
42%
Commonest cause of cardiac arrest in pregnancy
Anaesthetic (25%)
Commonest cause of maternal collapse
Vasovagal syncope
Epileptic seizures
MOH incidence
6 in 1000
Incidence of AFE
1.7 per 100, 000
Mortality rate with AFE
67 per 1000
Incidence of severe perioperative obstetric anaphylaxis
1-3.5 per 100, 000
Mortality rate from perioperative obstetric anaphylaxis
1%
Tryptase levels following anaphylaxis
After resuscitation has started
1-2 hours later
24 hours later
Aortocaval compression in pregnancy reduces CPR cardiac output by _____
From 30% to 10%
How to minimise aspiration pneumonitis risk? (Mendelsson syndrome)
Early intubation
Cricoid pressure
H1 anatagonists
Antacids
Left lateral tilt angle
15-30 degrees
Percentage cardiac output to placenta at term
10%
Aortacaval compression impairs venous return by ______
60%
Perimortem c/s should be done at ____ gestation and within ___ minutes of cardiac arrest
20+0
5 minutes
Fluid replacement in sepsis
30ml/kg within 3 hours
Target MAP in hypovolaemia
65mmHg
Intralipid infusion protocol
Bolus 15ml/kg over 1 minute then 15ml/kg/hr
Further bolus at 5 minute intervals if no return of circulation
Increase infusion to 30ml/kg/hr if needed
Maximum dose of intralipid
12ml/kg
Anaphylaxis treatment
1:1000 adrenaline 0.5ml IM
Repeat after 5 minutes
50 microgram IV bolus can be given by experienced Dr
Incidence of maternal cardiac arrest
2.78 per 100 000
Fetal survival after perimortem C/S
38%
Vasa praevia type 1 definition
Vessel connects to velamentous umbilical cord
Vasa praevia type 2 definition
Vessels connect placenta with succenturiate lobe
Vasa praevia prevalence
1 in 1200 to 1 in 5000
1 in 250 with IVF
Survival rates of vasa praevia when diagnosed antenatally with planned delivery
95%
Risk factors for vasa praevia
Velamentous cord insertion
Placenta praevia
Bilobed placenta
Succenturiate placental lobes
ART
What percentage of cases of vasa praevia resolve
20%
Rate of spontaneous version from breech to cephalic at term (primip)
8%
Rate of reversion to breech after ECV
3%
Factors associated with ECV success
Non-Engagement of breech
Palpable fetal head
Maternal weight <65kg
AFI >10
Tocolysis
Multiparous
Reason for c/s in labour after successful ECV
Slow progress
Fetal distress
When to perform ECV
37+0
Primips could have from 36 weeks
Rate of emergency c/s after ECV
1 in 200 within 24 hours
Indications for emergency c/s after failed ECV
Vaginal bleeding
Abnormal FH
Recurrence rate of breech presentation
9%
APH definitions
Spotting
Minor - <50ml and settled
Major - 50-1000ml with no sign of shock
Massive - >1000ml or sign of shock
Abruption incidence
Overall 0.5-1%
4.4% after 1
25% after 2
Severe abruption definition
Presence of:
(Maternal) shock, DIC, RBC requirement, hysterectomy, renal failure, death
(Fetal) IUD/NND, non-reassuring status, PTB, SGA
Risk factors for abruption
Previous
PET/essential HTN
FGR
PPROM
Old age
Multiparity
Smoking
Cocaine
Intrauterine infection
First trimester bleeding
Low BMI
ART
Abdominal trauma
Multiple pregnancy
Thrombophilia
Folic acid deficiency
Complications of abruption
Infection
Anaemia
Shock
DIC
AKI
Couvelere uterus
PPH
Ischaemia of distal organs (adrenal glands/pituitary)
Feto-maternal haemorrhage
Psychological sequalae
Risk of hysterectomy with placenta praevia + previous c/s
27 in 100
Extra peri-operative considerations for PAS
Ureteric stents
Iliac artery balloon insertion, fill after delivery for haemostasis
Risk of recurrence of uterine rupture
5%
Risk factors for uterine rupture
Previous c/s
Previous uterine surgery
Previous rupture
High parity
Induction/augmentation
Hyper stimulation
Mal presentation
Macrosomia
Uterine anomaly
Trauma
Uterine rupture causes CTG abnormalities in what percentage of cases
55-87%
Uterine rupture maternal mortality
17 per 100 000
Stage 1 DIC
Hypercoagulable state
Activation of clotting factors and development of microthrombi
Decreased clotting and increased platelet aggregation
Stage 2 DIC
Consumptive coagulants state
Increased consumption of platelets and clotting factors
Bleeding
Increased clotting
Decreased platelets
Decreased fibrinogen
Stage 3 DIC
Secondary fibrinolytic state
Formation of fibrin degradation products and plasmin
Marked bleeding
Increased thrombin time, decreased clot lysis time, increased fibrin degradation products
Prophylaxis of PPH
Correct DIC
Ensure euvolaemia with CVP 5-10mmHg
Synt
Rub up uterus
Keep patient warm
Re-assess DIC status
Iron requirement in pregnancy
2.5mg/day first trimester
6.66mg/day third trimester
Iron deficiency ferritin level
<30
B12 deficiency complications
PTB
Low birth weight
Maternal Complications of iron deficiency anaemia
PPH
Sepsis
PPD
Fatigue
Maternal death globally
Fetal complications of iron deficiency
Perinatal and neonatal mortality
SGA
PTB
Neurodevelopmental impairment
Oral iron replacement regime
Recheck Hb 2-3 weeks
Continue for 3 months or 6 weeks post partum
High dose folic acid for which women?
BMI >30
Taking AEDs
Previous affected pregnancy
Family history
T2DM and T1DM
Sickle cell disease
Thalassaemia
How is HbA2 measured
With HPLC test
HbA2 is _______ in sickle cell/thalassaemia carriers
Higher
Complications of thalassaemia
Hypersplenism
Delayed puberty
Hormone problems
Cardiomyopathy
Hepatitis, fibrosis, cirrhosis
Joint pains and osteoporosis
Chromosome deletion in alpha thalassaemia
16p
Alpha thalassaemia trait
2 abnormal alleles
Mild anaemia - hypochromic microcytic
Haemoglobin H disease
Unstable haemoglobins
Tetrameric gamma chains (Bart’s)
Tetrameric beta chains (H)
Blood film features of haemoglobin H disease
Microcytic hypochromic anaemia
Target cells
Heinz bodies (precipitated HbH)
Risk of cord prolapse with breech
1% footling breech (10% breech babies)
Contraindications to VBAC
Previous uterine rupture
Classical incision
Other absolute contraindications
Incidence of OASI after SVD
3.6% overall
Pri 5.4%
Multip 1.6%
Incidence of OASI after instrumental delivery
Pri 7.8%
Multip 4.8%
Repair of anorectal mucosa technique and suture
Continuous or interrupted
3-0 polyglactin
IAS repair technique and sutures
Repair separately from anorectal mucosa and EAS
Interrupted or mattress sutures, do not overlap
Use 3-0 PDS or 2-0 polyglactin
EAS repair technique and suture material
End to end for 3a and 3b
Can use overlapping for full thickness EAS tear
Use 3-0 PDS or 2-0 polyglactin
Prognosis of OASI
60-80% asymptomatic at 12 months
Mode of delivery after OASI
C/S if has symptoms after 1 year or abnormal endoanal ultrasound
Sub-occipito bregmatic diameter is
9.5cm
Flexed OA
Suboccipito-frontal diameter is
10cm
Incompletely flexed OA
Occipito-frontal diameter is
11.5cm
OP position
Submento-bregmatic diameter is
9.5cm
face presentation with head completely deflexed
Submento-vertical diameter is
11.5cm
Face presentation incompletely extended
Mento-vertical diameter is
13.5cm
Brow presentation
Cannot deliver vaginally
Risk of SGA with low PAPP-A
25%
BM targets in women with pre-existing diabetes
Fasting <5.3
1 hr Post prandial <7.8
2 hr post meal <6.4
Timing range >70% if using continuous monitoring
Best method to measure BM for pre-existing type 1 DM
Continuous glucose monitoring - reduces LGA, NNU admission and hypoglycaemia
Consider for type 2 when not meeting targets
Retinopathy screening timing
At booking
At 16-20 weeks of disease
28 weeks
No restrictions on treatment in pregnancy
Risk of type 2 diabetes after GDM
50% in 5 years
Offer insulin for GDM at diagnosis when
Fasting glucose >7
OR
Fasting 6-6.9 with fetal macrosomia or polyhydramnios
Start merformin/insulin for GDM after trial of diet when ____
Fasting BM > 5.3
BM >7.8 post meal
GDM timing of birth
Offer T+5 if uncomplicated
Deliver no later than T+6
HbA1c measurement for pre-existing DM
At booking and each trimester
Recommended delivery mode and timing after uterine transplant
37/40
Caesarean delivery