Fetal Structural Anomalies Flashcards by Ahalya Sathiyaselvan

What is the incidence of cleft lip?

0.15% live births

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

80%

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What ethnicity is most commonly affected by Cleft lip?

Asians

1: 600 Asians
1: 1100 Caucasians

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

Cleft lip: M > F

Isolated cleft palate: F > M

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

30%

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

50%

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

Cleft lip: 20%

Isolated cleft palate: 0.3%

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

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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What are the risk factors for Cleft lip / palate?

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

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When is cleft lip / palate surgically repaired?

Cleft lip: 2-3 months

Cleft palate: 9-18 months

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What is the incidence of congenital diaphragmatic hernia?

1;4:10,000 live births

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

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

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What is the definition of a congenital diaphragmatic hernia?

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

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What is congenital diaphragmatic hernia associated with?

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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What is the prognosis of congenital diaphragmatic hernia?

It depends on the severity of the lung hypoplasia

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

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

Deliver by 40/40

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

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What is the incidence of choroid plexus cyst?

1-3% in the normal population

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What are two examples of mid-trimester soft markers?

Choroid plexus cysts

Fetal echnogenic bowel

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What is choroid plexus cyst a soft marker for?

Association with T18 with a LR = 9

NOT associated with an increased risk of T21

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What are the disadvantages of identifying and reporting soft markers?

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

30-50%

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

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

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

When is it physiological to have midgut herniation?

First trimester

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

What is the definition of fetal echogenic bowel?

Abnormal bowel echogenicity equal to or greater than bone

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

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

What chromosomal abnormalities can be associated with fetal echogenic bowel?

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

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

Congenital infection - CMV is most common (tends to be focal) - Also toxoplasmosis ``` Cystic Fibrosis (tends to be multifocal) Fetal alcohol syndrome ```

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

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)

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

Monthly growth scans Due to increased risk of IUGR and intrauterine fetal death

How is fetal ventriculomegaly (cerebral) graded?

Lateral cerebral ventricular measurement Normal <10mm Mild 10-11.9mm Moderate 12-14.9mm Severe > 15mm

What is the differential diagnosis for fetal ventriculomegaly?

``` Aneuploidy Infection Syndromes Abnormal neuroanatomy Cerebral haemorrhage ```

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

5-17%

What is the pathophysiology of FNAIT?

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

What is the incidence of FNAIT?

1:8000 pregnancies

What is the management of FNAIT?

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

What is the incidence of non-immune fetal hydrops?

1:1500-3800

What is the definition of fetal hydrops?

USS findings of at least two of the following ``` Ascites Pleural effusion Pericardial effusion Skin oedema Polyhydramnios Placentomegaly ```

What percentage of hydrops is non-immune?

90%

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

<24/40: Aneuploidy > 24/40: Cardiovascular abnormalities

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

50-98% (Huge range, but take home message is that it’s high) Worse mortality with pleural effusions

What are the risk factors for gastroschisis?

Young maternal age Smoking Use of vasoactive agents

What is the definition of gastroschisis?

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)

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

Consideration of 37-38/40 Mode of delivery as per normal obstetric indications

What is the survival rate of liveborns with gastroschisis?

90-95%

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

IUFD - 10% | SGA - 20%

What is the incidence of Fetal Alcohol Syndrome

1:1000 births 4% in heavy alcohol drinkers Up to 33% in women who drink > 18units per day

What are the neonatal effects of fetal alcohol exposure?

Neonatal withdrawal - irritability, hypotonia, tremors Neonatal jaundice

What are the diagnostic criteria / levels for Fetal Alcohol Syndrome

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

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

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

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

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