Anomaly Screening Flashcards
What is the most common pathophysiology of trisomy 21
Non- dysjunction (95%)
Translocation (5%)
Incidence of trisomy 21
1:700 live births
What conditions cause low AFP(3)
Trisome 21
Trisomy 18
Diabetes mellitus
What causes high AFP (5)
- neural tube defects
- exomphalos
- anencephaly
- duodenal atresia
- multiple gestation
What are the features of a meningomyelocele
- banana shaped cerebellum 99%
- hydrocephalus 70%
Classification of ventriculomegaly
- mild: lateral ventricle 10-12mm
- mod: LV 12.1-15mm
- sev: LV >15mm
Most common site of spina bifida
Lumbosacral region
Choroid plexus cyst + fetal anomalies
Likely diagnosis?
Trisomy 18 (50%)
Indications for fetal echocardiogram
History related(4)
- family history of CHD esp mother (6%) or father (2%)
- previous child with CHD
- uncontrolled pregestational diabetes
- teratogen- lithium
Indications for fetal echocardiogram
Pregnancy related (4)
- increased nuchal translucency
- other fetal anomalies
- fetal hydrops
- fetal arrhythmia
Most common features of trisomy 21(6)
- duodenal atresia
- AVSD
- VSD
- nuchal thickening
- mild ventriculomegaly
- sandal gap toe
Features of trisomy 18 (5)
- choroid plexus cyst
- clenched fist
- rockerbottom feet
- strawberry skull
- micrognathia
Features of trisomy 13 (5)
- holoprosencephaly
- midline or bilateral facial cleft
- iugr
- polydactyly
- Cardiovascular
Incidence of anencephaly
1:1000
When does physiological gut herniation occur
9-12 weeks
What is megacystitis
Fetal bladder longitudinal length >7mm
Incidence 0.06%
What is the significance of soft markers on ultraosund
- can be seen In normal pregnancies
- not diagnostic of structural defects
- concern should be raised if associated with other defects or soft markers
What is echogenic bowel
Hyper echogenicity of fetal bowel that should be grey like liver but white as bone.
What conditions are associated with echogenic bowel
- trisomy 13,18 21
- bowel Obstruction
- cystic fibrosis
- fetal growth restriction
What is the significance of omphalocele
- 10-40% associated with chromosomal anomalies (trisomy 21,18,13)
- 60% associated with other structural abnormalities such as cardiac or NTD
- Requires invasive testing for karyotyping
Incidence of omphalocele
3.4 : 10000 pregnancies
What is the prevalence of encephalocele
0.8-5:10000 live births
What is the most common syndrome associated with encephalocele
Autosomal recessive
Meckel gruber syndrome
- occipital encephalocele
-microcephaly
-micropthalmia
- polycystic kidneys
- ambiguous genitalia
- polydactyly
- cleft lip and palate
What is associated with a low Papp -a(5)
- spontaneous miscarriage
- gestational hypertension
- pre eclampsia
- low birth weight
- preterm delivery
What specific perinatal outcome is associated with a raised afp
- placental abruption
What is associated with raised hcg/inhibinA
- ptb
- ghtn
- pre eclampsia
- fetal demise after 24 weeks
- fgr
What specific perinatal outcome is associated with low ue3
Oligohydramnios
