Intrauterine Growth Restriction ✅

Question 1

Why is an infant’s gestation and birth weight important?

Answer 1

It influences the nature of the medial problems likely to be encountered in the neonatal period

Question 2

What is low birth weight defined as?

Answer 2

<2.5kg

Question 3

What % of babies in the UK have low birth weight?

Answer 3

7%

Question 4

What % of neonatal deaths are accounted for by babies with low birth weight?

Answer 4

Around 70%

Question 5

What is small for gestational age defined as?

Answer 5

Babies with birth weight below the 10th centile for their gestational age

Question 6

What is true of the majority of infants born SGA?

Answer 6

They are normal, but constitutionally small

Question 7

What are the potential scenarios resulting in SGA babies?

Answer 7

• Have grown normally but are small
• Have experienced intrauterine growth restriction, i.e. have failed to reach their full genetically determined growth potential

Question 8

How do babies with IUGR appear?

Answer 8

Thin and malnourished

Question 9

Are all IUGR babies SGA?

Answer 9

No, babies with a birth weight above the 10th centile may be growth restricted, e.g. a fetus growing along 80th centile who develops growth failure and falls to 20th centile

Question 10

What is the term SGA sometimes restricted to?

Answer 10

Babies whose birth weight falls below the 2nd centile

Question 11

Why is the term SGA sometimes restricted to babies with birth weights below the 2nd centile?

Answer 11

Because the incidence of congenital abnormalities and neonatal problems is higher in these babies

Question 12

What can fetal centiles be customised to take into account?

Answer 12

• Maternal characteristics
• Gestation
• Gender

Question 13

What maternal characteristics might fetal centiles be customised on the basis of?

Answer 13

• Weight
• Height
• Parity
• Ethnicity

Question 14

What is the advantage of customising fetal centiles?

Answer 14

More predictive of morbidity and mortality

Question 15

What does the use of the term ‘intrauterine growth restriction’ to describe a fetus imply?

Answer 15

Pathological restriction of genetic growth potential

Question 16

How can IUGR be identified/monitored?

Answer 16

Looking for evidence of fetal compromise

Question 17

What evidence of fetal compromise might be identified in IUGR?

Answer 17

• Reduced liquor volume

- Abnormal Doppler waveforms

Question 18

What has IUGR traditionally been classified as?

Answer 18

Symmetrical or asymmetrical

Question 19

What is the more common type of IUGR?

Answer 19

Asymmetrical

Question 20

What is meant by asymmetrical growth restriction?

Answer 20

The weight or abdominal circumference lies on a lower centile than that of the head

Question 21

What causes asymmetrical IUGR?

Answer 21

When the placenta fails to provide adequate nutrition late in pregnancy

Question 22

Why is brain growth spared at the expense of in asymmetrical IUGR?

Answer 22

• Liver glycogen

- Skin fat

Question 23

What can cause the uteroplacental dysfunction leading to asymmetrical IUGR?

Answer 23

• Maternal pre-eclampsia
• Multiple pregnancy
• Maternal smoking
• Idiopathic

Question 24

What happens to asymmetrical IUGR infants after birth?

Answer 24

They rapidly put on weight

Question 25

What happens in symmetrical growth restriction?

Answer 25

The head circumference is equally reduced

Question 26

What does symmetrical growth restriction suggest?

Answer 26

A period of poor intrauterine growth starting in early pregnancy

Question 27

What is symmetrical growth restriction usually due to?

Answer 27

A small but normal fetus

Question 28

What are the pathological causes of symmetrical IUGR?

Answer 28

- Fetal chromosomal disorder or syndrome - Congenital infection - Maternal drug and alcohol abuse - Chronic medical condition or malnutrition

Question 29

What happens to infants with symmetrical IUGR after birth?

Answer 29

They are more likely to remain small permanently

Question 30

What is a fetus with IUGR at increased risk of?

Answer 30

- Intrauterine hypoxia/intrauterine death | - Asphyxia during labour and delivery

Question 31

What is the purpose of close monitoring of an IUGR fetus?

Answer 31

Determine the optimal time for delivery

Question 32

What does progressive uteroplacental failure result in?

Answer 32

- Reduced growth in femur length and abdominal circumference - Reduced amniotic fluid volume - Abnormal umbilical artery Doppler waveform - Redistribution of blood flow in the fetus - Abnormal ductus venosus Doppler waveform - Reduced fetal movements - Abnormal CTG - Intrauterine death or hypoxic damage to the fetus

Question 33

What causes the abnormal umbilical artery Doppler in progressive uteroplacental failure?

Answer 33

Increased placental impedance

Question 34

What is found on umbilical artery Doppler in progressive uteroplacental failure?

Answer 34

Absent and then reversed end-diastolic flow velocity

Question 35

How is blood redistributed when there is progressive uteroplacental failure?

Answer 35

Increased to brain, reduced to GI tract, liver, skin, and kidneys

Question 36

What does the abnormal ductus venosus Doppler waveform in progressive uteroplacental failure?

Answer 36

Diastolic cardiac dysfunction

Question 37

What are the risks/complications of IUGR after birth?

Answer 37

- Hypothermia - Hypoglycaemia - Hypocalcaemia - Polycythaemia

Question 38

Why are IUGR babies at risk of hypothermia after birth?

Answer 38

Because of their relatively large surface area

Question 39

What is polycythaemia defined as?

Answer 39

Venous haematocrit >0.65

Question 40

How does the umbilical artery Doppler waveform appear in the healthy fetus?

Answer 40

Forward flow in the umbilical artery throughout systole and diastole

Question 41

How does the umbilical artery Doppler waveform appear in IUGR due to placental disease?

Answer 41

Reduced, then absent or reversed flow during diastole

Question 42

What causes the abnormal umbilical artery Doppler in IUGR due to placental disease?

Answer 42

Increased resistance in the placenta due to loss of placental villi or pre-eclampsia

Question 43

What is indicated if end-diastolic flow is absent on umbilical artery Doppler in IUGR?

Answer 43

Detailed Doppler studies of the middle cerebral artery and ductus venosus

Question 44

What happens to blood flow as IUGR becomes increasingly severe?

Answer 44

There is redistribution of fetal blood flow, with an increase in flow to the brain and increased end-diastolic velocity

Question 45

What should evidence of cerebral redistribution in a fetus indicate?

Answer 45

A need for invasive regular monitoring

Question 46

What does a ductus venosus Dopper reflect?

Answer 46

The physiological state of the right heart

Question 47

What may be found on ductus venosus Doppler in IUGR?

Answer 47

Reversed flow during atrial contraction (in the second trimester)

Question 48

What does reversed flow during atrial contraction in a second trimester IUGR represent?

Answer 48

Cardiac decompensation

Question 49

Why is ductus venosus Doppler a useful test?

Answer 49

Finding of reversed flow during atrial contraction is a better predictor of stillbirth than umbilical artery Doppler alone

Question 50

What is timing of delivery based on in IUGR?

Answer 50

- Doppler findings - Gestation - Estimated fetal weight