Fetal Structural Anomalies Flashcards

1
Q

What is the incidence of cleft lip?

A

0.15% live births

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2
Q

What % of foetuses with cleft lip will also have cleft palate

A

80%

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3
Q

What ethnicity is most commonly affected by Cleft lip?

A

Asians

1: 600 Asians
1: 1100 Caucasians

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4
Q

What is the difference in incidence between genders with cleft lip and cleft palate?

A

Cleft lip: M > F

Isolated cleft palate: F > M

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5
Q

What % of foetuses with cleft lip have it as part of a syndrome?

A

30%

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6
Q

What % of foetuses with cleft palate have it as part of a syndrome?

A

50%

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7
Q

What is the antenatal detection rate of cleft lip vs isolated cleft palate?

A

Cleft lip: 20%

Isolated cleft palate: 0.3%

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8
Q

What are the four types in the classification system of Cleft Lip and palate?

A

I - Unilateral cleft lip (failure of lip / palate fusion)
II - Unilateral cleft lip and palate (failure of lip / palate fusion)
III - Bilateral cleft lip and palate (failure of lip / palate fusions)
IV - Midline cleft lip and palate (agenesis of the intermaxillary process) - highest risk of aneuploidy and associated anomalies

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9
Q

What are the risk factors for Cleft lip / palate?

A

Genetic defects - Sonic hedgehog, TGF-alpha
Medications - retinoids acid, valproic acid, methotrexate
Smoking, alcohol
Folate deficiency, Maternal obesity

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10
Q

When is cleft lip / palate surgically repaired?

A

Cleft lip: 2-3 months

Cleft palate: 9-18 months

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11
Q

What is the incidence of congenital diaphragmatic hernia?

A

1;4:10,000 live births

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12
Q

What is the incidence of left sided vs right sided vs bilateral congenital diaphragmatic hernias?

A

Left sided: 86%
Right sided: 13%
Bilateral: 1-2%

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13
Q

What is the definition of a congenital diaphragmatic hernia?

A

Developmental discontinuity of the diaphragm that allows abdominal content (may include stomach, bowel and liver) to herniate into the chest

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14
Q

What is congenital diaphragmatic hernia associated with?

A

Pulmonary hypoplasia and pulmonary hypertension***
- associated morbidity and mortality
Cardiac defects (28% association). Therefore, if CDH should do Fetal Echo
Polyhydramnios - oesophageal compression
Hydrops - compression of great vessels

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15
Q

What is the prognosis of congenital diaphragmatic hernia?

A

It depends on the severity of the lung hypoplasia

Severe: majority die
Moderate: 40-60% survival
Mild: 60-90% survival

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16
Q

What is the recommended timing and mode of delivery for congenital diaphragmatic hernia?

A

Deliver by 40/40

Routine obstetric indications for CS i.e. can have NVD

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17
Q

What is the incidence of choroid plexus cyst?

A

1-3% in the normal population

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18
Q

What are two examples of mid-trimester soft markers?

A

Choroid plexus cysts

Fetal echnogenic bowel

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19
Q

What is choroid plexus cyst a soft marker for?

A

Association with T18 with a LR = 9

NOT associated with an increased risk of T21

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20
Q

What are the disadvantages of identifying and reporting soft markers?

A

Patient anxiety
Need for further counselling
Significant time and expense
Decision making regarding proceeding to further invasive testing
Risk of miscarriage / SROM / PTB from invasive testing

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21
Q

What percentage of foetuses with T18 will have a choroid plexus cyst?

A

30-50%

80% of babies with T18 will also have another structural anomaly

22
Q

What is the management for a finding of a choroid plexus cyst?

A

Indication for detailed careful USS rather than invasive testing

If confirmed to be isolated (unilateral or bilateral)
No further discussion, investigation or follow up USS

23
Q

When is it physiological to have midgut herniation?

A

First trimester

24
Q

What is the incidence of fetal echogenic bowel in the second trimester?

A

1%

25
Q

What is the definition of fetal echogenic bowel?

A

Abnormal bowel echogenicity equal to or greater than bone

26
Q

What is the significance of a finding of fetal echogenic bowel?

A

In isolation, it is a benign condition

However, it can be associated with increased risk of chromosomal and non-chromosomal fetal abnormalities and prognosis is less favourable in these cases

27
Q

What chromosomal abnormalities can be associated with fetal echogenic bowel?

A

Most commonly T21 (RR 5.5)

But also T13, T18 and sex chromosomes

It is an isolated finding in 9% of foetuses with aneuploidy
Tends to be multi focal

28
Q

What are some non-chromosomal conditions associated with fetal echogenic bowel?

A

Congenital infection

  • CMV is most common (tends to be focal)
  • Also toxoplasmosis
Cystic Fibrosis (tends to be multifocal)
Fetal alcohol syndrome
29
Q

What are some differential diagnoses for a finding of fetal echogenic bowel?

A
  1. Intra-amniotic bleeding - swallowing of blood
  2. Congenital malformations of the bowel
  3. IUGR with mesenteric ischaemia (increased risk of perinatal morbidity and mortality)
30
Q

What is the management for a pregnancy affected by isolated fetal echogenic bowel?

A

Monthly growth scans

Due to increased risk of IUGR and intrauterine fetal death

31
Q

How is fetal ventriculomegaly (cerebral) graded?

A

Lateral cerebral ventricular measurement

Normal <10mm
Mild 10-11.9mm
Moderate 12-14.9mm
Severe > 15mm

32
Q

What is the differential diagnosis for fetal ventriculomegaly?

A
Aneuploidy
Infection
Syndromes
Abnormal neuroanatomy
Cerebral haemorrhage
33
Q

For a fetus diagnosed with ventriculomegaly, what percentage will be affected by aneuploidy?

A

5-17%

34
Q

What is the pathophysiology of FNAIT?

A

Maternal paternal platelet type incompatibility
Leads to production of
Maternal platelet specific alloantibodies
Leads to
Fetal / neonatal thrombocytopenia

35
Q

What is the incidence of FNAIT?

A

1:8000 pregnancies

36
Q

What is the management of FNAIT?

A

IVIG

Shown to improve the platelet count in foetuses at risk of NAIT

37
Q

What is the incidence of non-immune fetal hydrops?

A

1:1500-3800

38
Q

What is the definition of fetal hydrops?

A

USS findings of at least two of the following

Ascites
Pleural effusion
Pericardial effusion
Skin oedema 
Polyhydramnios
Placentomegaly
39
Q

What percentage of hydrops is non-immune?

A

90%

40
Q

What are the underlying conditions that lead to non-immune hydrops?

A

<24/40: Aneuploidy

> 24/40: Cardiovascular abnormalities

41
Q

What is the perinatal mortality rate of non-immune hydrops?

A

50-98%

(Huge range, but take home message is that it’s high)

Worse mortality with pleural effusions

42
Q

What are the risk factors for gastroschisis?

A

Young maternal age
Smoking
Use of vasoactive agents

43
Q

What is the definition of gastroschisis?

A

Full thickness anterior abdominal wall defect with bowel protruding through the defect

Usually occurs on the right side of a normally inserting umbilical cord

Defect is NOT covered by membrane (as opposed to omphalocoele)

44
Q

What is the timing and mode of delivery for a pregnancy affected by gastroschisis?

A

Consideration of 37-38/40

Mode of delivery as per normal obstetric indications

45
Q

What is the survival rate of liveborns with gastroschisis?

A

90-95%

46
Q

What is the risk of
A) IUFD
B) SGA
With Gastroschisis

A

IUFD - 10%

SGA - 20%

47
Q

What is the incidence of Fetal Alcohol Syndrome

A

1:1000 births

4% in heavy alcohol drinkers
Up to 33% in women who drink > 18units per day

48
Q

What are the neonatal effects of fetal alcohol exposure?

A

Neonatal withdrawal
- irritability, hypotonia, tremors

Neonatal jaundice

49
Q

What are the diagnostic criteria / levels for Fetal Alcohol Syndrome

A
  1. Confirmed maternal alcohol exposure
  2. Dysmorphic features: short palpebral fissure, flattened upper lip, Phil true and mid face
  3. Fetal growth restriction
  4. CNS involvement
    - reduced cranial size at birth
    - structural brain anomalies: microcephaly, corpus callosum agenesis, cerebellar hypoplasia
    - Neurological signs: impaired fine motor skills, neurosensory hearing loss, poor tandem gait, poor hand-eye coordination
50
Q

Other than the Diagnostic criteria for Fetal Alcohol Syndrome, what are some manifestations of the Syndrome?

A

Mental retardation (most common and serious)
Congenital heart disease: ASD or VSD
Renal hypoplasia, hydronephrosis, bladder diverticula
Short stature and skeletal deformities

51
Q

What are the long term effects of fetal alcohol syndrome / exposure?

A

Increased risk of neglect and abuse
Attention and memory deficits, hyperactivity
Learning difficulties
Dose-response relationship between alcohol intake (especially first trimester) and reduced height and weight in children
Increased risk of aggressive behaviour, psychiatric disorders and substance abuse