Obs T3 Flashcards
(30 cards)
What are the complications associated with monochorionic pregnancy?
TTTS, TRAP, twin embolisation syndrome, acardiac twin, demise of co-twin, umbilical cord knots/thrombosis, increased risk of birth defects
TTTS: Twin-to-twin transfusion syndrome, TRAP: Twin reversed arterial perfusion.
What are the stages of TTTS according to the Quintero system?
1 - oligo/poly
2 - no bladder
3 - abnormal Dopplers
4 - hydrops
5 - demise
Oligo/poly refers to oligohydramnios and polyhydramnios.
What is the management approach for TTTS?
O&G tertiary referral, look for TAPS, reassurance and counselling, close monitoring, laser ablation if <26 weeks
TAPS: Twin anemia-polycythemia sequence.
What is the pathology of TRAP?
Arterial-arterial placental anastomosis, small pump twin pumps blood to the large non-viable acardiac twin
The acardiac twin has reversed umbilical artery flow.
What is the differential diagnosis for IUGR?
SGA, wrong dates
SGA: Small for gestational age.
How can you differentiate SGA from IUGR?
SGA will grow parallel to centile lines, IUGR will cross centiles
In asymmetric IUGR, abdominal circumference is >30% than head circumference.
What are the causes of symmetrical vs asymmetrical IUGR?
Symmetrical: aneuploidy, TORCH, alcohol, smoking; Asymmetrical: placental insufficiency, pre-eclampsia
TORCH: Toxoplasmosis, Other, Rubella, Cytomegalovirus, Herpes simplex virus.
How is fetal biometry performed?
BPD, HC, AC, FL
BPD: Biparietal diameter, HC: Head circumference, AC: Abdominal circumference, FL: Femur length.
What are the associations with macrosomia?
Maternal obesity, GDM, polyhydramnios, Beckwith Wiedemann
GDM: Gestational diabetes mellitus.
What complications are associated with macrosomia?
Birth trauma, birth asphyxia, neonatal hypoglycaemia, meconium aspiration
What is the management for macrosomia?
O&G referral, glucose tolerance test, risk of birth complications
Complications include protracted labour, PPH, vaginal laceration.
What is the definition of oligohydramnios?
Deepest pocket <2cm, AFI <5cm
AFI: Amniotic fluid index.
What are the causes of oligohydramnios?
Demise, renal abnormality, IUGR, PROM, aneuploidy
What is the definition of polyhydramnios?
Deepest pocket >8cm, AFI >25cm
What are the causes of polyhydramnios?
Maternal diabetes, fetal neural tube defects, cardiac/thoracic anomalies, hydrops
What indicates abnormal Dopplers in the third trimester?
High resistance UA, low resistance MCA, reversal of A wave in DV, CPR <1, high MCA PSV MoM >1.6, uterine artery diastolic notching
UA: Umbilical artery, MCA: Middle cerebral artery, DV: Ductus venosus.
Describe the ductus venosus waveform.
S wave, D wave, A wave
S wave is the highest peak, A wave is the lowest but still in forward direction.
What is the significance of the ductus venosus in the first trimester?
Abnormal increased PI is a marker for aneuploidy
PI: Pulsatility index, includes risk for T21, T18, T13, Turner syndrome.
What is the cerebroplacental ratio?
CPR = MCA PI / UA PI
If <1, indicates fetal distress and increased emergency C-section rates.
What is the management for abnormal Dopplers indicating fetal distress?
Obstetric emergency, discuss with O&G for consideration of delivery in 24 hours
What are the risk factors for retroplacental abruption/haemorrhage?
Pre-eclampsia, prior abruption, PROM, >35yo, smoking, cocaine, multiparity
What is the aetiology of retroplacental abruption/haemorrhage?
Rupture of uterine spiral arteries
What is the management for retroplacental abruption/haemorrhage?
Monitor, consider delivering
What is the size definition for placentomegaly?
> 4cm
