SGA and IUGR Flashcards

1
Q

What is the definition of SGA?

A

BW <10th centile or AC <10th centile

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2
Q

What is the definition of severe SGA?

A

BW <3rd centile or AC <3rd centil

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3
Q

______% SGA foetuses are constitutionally small

A

50-70%

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4
Q

What does fetal growth restriction imply?

A

Pathological restriction of the genetic growth potential

Fetal compromise

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5
Q

What is the pathophysiology of SGA secondary to placental insufficiency?

A

Failure of trophoblast invasion of the myometrial uterine spiral arteries
Reduced uteroplacental blood flow

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6
Q

What is the relative risk of SGA, if previous pregnancy affected by SGA?

A

2

Higher if more than one previous pregnancy affected

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7
Q

What is the relative risk of SGA with a low PAPP-A

A

3

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8
Q

What are the 6 categories of causes of SGA?

A
Constitutionally small
Structural or chromosomal anomaly
Inborn errors of metabolism
Infection - TORCH
Placental insufficiency
Maternal conditions (affecting placenta really)
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9
Q

What is the main risk with SGA?

A

Increased perinatal mortality and morbidity

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10
Q

Unidentified SGA foetuses have a ___ fold increased risk of adverse outcomes

A

4

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11
Q

Why should SFH be plotted on a customised chart?

A

May improve prediction of SGA neonate

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12
Q

What is the management of abnormal uterine artery doppler at 20-24/40

A

Serial USS measurement and UAPI commencing 26-28/40

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13
Q

Should BPP be used in preterm SGA?

A

No

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14
Q

STV < 3 is associated with…

A

Higher rate of metabolic acid anemia and early neonatal death

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15
Q

What was the Cochrane Review finding re: Umbilical artery PI in high risk pregnancies

A

Pregnancies at risk of placental insufficiency should be monitored with this

UAPI measurement may decrease the
- mortality rate
And lead to fewer IOLs and CS

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16
Q

What does the ductus venosus doppler reflect?

Pathophysiology

A

Atrial pressure-volume changes during the cardiac cycle
As FGR worsening, velocity reduces in the DV a wave owing to increased afterload and preload, as well as increased end-diastolic pressure

Reflects acid anemia

Retrograde a-wave and pulsatile flow in the UV signifies the onset of overt fetal cardiac compromise

17
Q

What is the role of MCA PI in preterm SGA?

A

Not to be used to time delivery (RCOG)

No evidence that it correlates with acid-base physiology

Low predictive value re: adverse outcome

Delivery at 37/40 (RCOG)

18
Q

What does an abnormal MCA PI represent?

Pathophysiology

A

Cerebral vasodilation
Redistribution of blood
Brain sparing

19
Q

What is the gestational cut-off for early vs late onset IUGR

A

32/40

20
Q

What was the aim, interventions and outcomes of the DIGITAT trial?

A

Aim: To compare the effect of IOL with expectant monitoring for IUGR near term
Participants: singleton, 36/40, suspected IUGR
Interventions: IOL vs expectant management. Randomly allocated
Primary outcome: composite neonatal outcome, operative delivery

Results. IOL babies were

  • delivered 10 days earlier
  • weighed 130g less
  • no important differences in adverse outcomes
  • no difference in CS rates
21
Q

What % of FGR babies will experience intrapartum asphyxia?

A

50%

22
Q

What is the perinatal mortality rate for FGR babies?

A

80 per 1000

23
Q

What % of stillbirths are FGR?

A

Preterm stillbirth 50%

Term stillbirth 25%

24
Q

Regarding UAPI:
What are the benefits?

When are they indicated?

How often should they be done?

A

Reduces:

  • Perinatal mortality
  • IOL
  • CS rate
  • Use of hospital resources.

Indications: FGR, RFMs, pregnancy HTN disorders.

Every 2 weeks if normal
Twice a week if abnormal with forward EDF.
Every day if abnormal with absent or reversed EDF.

25
Q

What are the indications for MCAPI?

A
  • SGA with ABNORMAL doppler, any gestation.
  • SGA with NORMAL doppler, only after 34 weeks
  • MCDA with TTTS
26
Q

What is the pathophysiology behind the ductus venosus doppler findings associated with FGR?

A

Abnormal DVPI >95th cent.
Abnormal DV A-wave is absent or reversed.

DV A-wave represents pressure created by right atrial contraction in late diastolic phase and causes a variable amount of reverse flow.

  • Increased umbilical artery resistance –> impaired fetal cardiac performance and increased CVP –> reduced DV diastolic flow and reduction in A-wave.
  • Absent or reversed DV A-wave indicates cardiovascular instability and can be a sign of impending acidaemia and fetal death.
27
Q

What are the benefits of measuring the DV A-wave?

A

TRUFFLE study: improved 2 year survival without impairment when delivery triggered by absent A-wave.

28
Q

When should DV doppler (DVPI and A-wave) be measured?

A

For timing of delivery decision making for PRETERM infants:

  • SGA with abnormal UAPI and reduced MCAPI
  • MCDA twins with TTTS or sIUGR.
29
Q

What is the progression of doppler changes in severe IUGR?

A

Early signs:

  • UAPI
  • MCAPI
  • UA AEDF

Late signs:

  • UA REDF
  • DVPI
  • DV absent or reversed a wave
30
Q

Describe the role of CTG in the care of preterm SGA fetuses:

A

Should not be only surveillance method as no improvement in perinatal mortality.

STV from computerised analysis: most powerful predictor of fetal wellbeing.
<=3 ms associated with higher rate of metabolic acidaemia (50 vs 10%) and early neonatal death (8 vs 0.5%).

31
Q

What the the indications for inpatient mgmt of FGR pregnancies?

A
  • Umbilical artery A/REDF and EFW >350 g
  • No fetal growth
  • Associated oligohydramnios
  • Reduced or absent FMs
32
Q

In the context of an FGR pregnancy:
When should antenatal corticosteroids be given?

What side-effect can affect fetal surveillance?

A

Indicated when umbilical artery EDF becomes absent or reversed.

Side-effects:

  • Reversed FHR variability
  • RFMs by 50%
  • Cessation of fetal breathing movements.
  • Temporary improvement in doppler studies.
33
Q

Regarding FGR pregnancy:

What are the indications for delivery and timings (aside from safety net abnormal CTG findings?).

A

<32 weeks: Abnormal DV doppler, umbilical vein pulsations and/or abnormal cCTG with umbilical artery A/REDF.
- Consider between 30-32 weeks even if DV doppler normal.

By 34 weeks: UAPI EDF
By 37 weeks: UAPI or MCAPI abnormal.
By 38-40 weeks: UAPI normal
After 34 weeks: static growth +/- abnormal UAPI with forward EDF.