Anomaly Screening

Question 1

What is the most common pathophysiology of trisomy 21

Answer 1

Non- dysjunction (95%)
Translocation (5%)

Question 2

Incidence of trisomy 21

Answer 2

1:700 live births

Question 3

What conditions cause low AFP(3)

Answer 3

Trisome 21
Trisomy 18
Diabetes mellitus

Question 4

What causes high AFP (5)

Answer 4

• neural tube defects
• exomphalos
• anencephaly
• duodenal atresia
• multiple gestation

Question 5

What are the features of a meningomyelocele

Answer 5

• banana shaped cerebellum 99%
• hydrocephalus 70%

Question 6

Classification of ventriculomegaly

Answer 6

• mild: lateral ventricle 10-12mm
• mod: LV 12.1-15mm
• sev: LV >15mm

Question 7

Most common site of spina bifida

Answer 7

Lumbosacral region

Question 8

Choroid plexus cyst + fetal anomalies
Likely diagnosis?

Answer 8

Trisomy 18 (50%)

Question 9

Indications for fetal echocardiogram
History related(4)

Answer 9

• family history of CHD esp mother (6%) or father (2%)
• previous child with CHD
• uncontrolled pregestational diabetes
• teratogen- lithium

Question 10

Indications for fetal echocardiogram
Pregnancy related (4)

Answer 10

• increased nuchal translucency
• other fetal anomalies
• fetal hydrops
• fetal arrhythmia

Question 11

Most common features of trisomy 21(6)

Answer 11

• duodenal atresia
• AVSD
• VSD
• nuchal thickening
• mild ventriculomegaly
• sandal gap toe

Question 12

Features of trisomy 18 (5)

Answer 12

• choroid plexus cyst
• clenched fist
• rockerbottom feet
• strawberry skull
• micrognathia

Question 13

Features of trisomy 13 (5)

Answer 13

• holoprosencephaly
• midline or bilateral facial cleft
• iugr
• polydactyly
• Cardiovascular

Question 14

Incidence of anencephaly

Answer 14

1:1000

Question 15

When does physiological gut herniation occur

Answer 15

9-12 weeks

Question 16

What is megacystitis

Answer 16

Fetal bladder longitudinal length >7mm

Incidence 0.06%

Question 17

What is the significance of soft markers on ultraosund

Answer 17

• can be seen In normal pregnancies
• not diagnostic of structural defects
• concern should be raised if associated with other defects or soft markers

Question 18

What is echogenic bowel

Answer 18

Hyper echogenicity of fetal bowel that should be grey like liver but white as bone.

Question 19

What conditions are associated with echogenic bowel

Answer 19

• trisomy 13,18 21
• bowel Obstruction
• cystic fibrosis
• fetal growth restriction

Question 20

What is the significance of omphalocele

Answer 20

• 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

Question 21

Incidence of omphalocele

Answer 21

3.4 : 10000 pregnancies

Question 22

What is the prevalence of encephalocele

Answer 22

0.8-5:10000 live births

Question 23

What is the most common syndrome associated with encephalocele

Answer 23

Autosomal recessive

Meckel gruber syndrome
- occipital encephalocele
-microcephaly
-micropthalmia
- polycystic kidneys
- ambiguous genitalia
- polydactyly
- cleft lip and palate

Question 24

What is associated with a low Papp -a(5)

Answer 24

• spontaneous miscarriage
• gestational hypertension
• pre eclampsia
• low birth weight
• preterm delivery

Question 25

What specific perinatal outcome is associated with a raised afp

Answer 25

- placental abruption

Question 26

What is associated with raised hcg/inhibinA

Answer 26

- ptb - ghtn - pre eclampsia - fetal demise after 24 weeks - fgr

Question 27

What specific perinatal outcome is associated with low ue3

Answer 27

Oligohydramnios