Small for dates pregnancy

Question 1

Define Small for gestational age

Answer 1

birth weight <10th centile

Question 2

What is intrauterine growth restriction?

Answer 2

fetus that has failed to reach its growth potential due to
pathological restriction

Question 3

What is the relationship between IUGR and SGA?

Answer 3

All IUGR babies can become SGA

Not all SGA babies are IUGR

Question 4

What is symmetrical IUGR? What is it caused by? When does it affect the foetus?

Answer 4

proportional growth restriction in all parts of the foetus.

Caused by intrinsic factors e.g. genetic abnormalities + intrauterine infections.

Affects the foetus early in gestation.

Question 5

What is asymmetrical IUGR? What is it caused by? When does it affect the foetus?

Answer 5

disproportionate growth restriction with a greater decrease in foetal body + limbs compared to head circumference.

Caused by extrinsic factors e.g. placental insufficiency.

O2 + nutrients directed towards vital organs (brain + heart) bypassing other organs (e.g. liver, muscle + fat tissue).
Affects foetus later in gestation.

Question 6

Give 4 maternal risk factors for IUGR

Answer 6

Age >40y
Previous pregnancy with IUGR
Smoker
Cocaine use

(+Low pre-pregnancy weight/ Under nutrition)

Question 7

Give 6 maternal medical conditions that are risk factors for IUGR

Answer 7

Pre-eclampsia
AI disease: SLE
Thrombophilias: antiphospholipid syndrome, sickle cell disease
Renal disease
Diabetes
Essential/ gestational HTN

Question 8

Give 3 uteroplacental risk factors for IUGR

Answer 8

Placental insufficiency caused by maternal/ pregnancy-related conditions

Placenta praevia or placental abruption

Multiple gestation

Question 9

Give 3 foetal risk factors for IUGR

Answer 9

Congenital/ early IUI: toxoplasmosis, rubella, CMV, varicella, TB, HSV, HIV, syphilis, malaria

Genetic abnormalities: aneuploidy

Congenital anomalies: tracheoesophageal fistula, cyanotic CHD, gastroschisis, or neural tube defects

Question 10

What are the 4 most common causes of IUGR in practice?

Answer 10

Idiopathic/Unknown
Preeclamspia
APH
Smoking

Question 11

How does fundal height relate to gestation?

Answer 11

Fundal height in cm should equal weeks gestation

Question 12

Give 5 circumstances in which fundal height may be inaccurate

Answer 12

High BMI
Fibroids
Multiple gestation
Polyhydramnios + Oligohydramnios
Non longitudinal lie

Question 13

How should IUGR/ SGA be assessed?

Answer 13

Assess at booking for risk factors

1 major RF: serial USS measurements + umbilical artery doppler at 26-28w
>,3 minor RFs: uterine artery doppler at 20-24w

Question 14

What USS investigations can be used for IUGR?

Answer 14

Fetal measurements: Abdo circumference + estimated fetal weight

Amniotic fluid assessment

Dopplers

Question 15

What monitoring is required for IUGR pregnancies?

Answer 15

Umbilical artery Doppler USS every 2w
Monitor foetal movements

Question 16

What does uterine artery doppler show?

Answer 16

Low or high resistance in uterine arteries at 20-24w
Marker of increased risk
Impedance to flow a/w adverse outcomes eso. pre-eclampsia + IUGR
“Notching”

Question 17

What does umbilical artery doppler identify?

Answer 17

Fetal compromise in pregnancies complicated by IUGR

Question 18

What 3 patterns may be seen on umbilical artery doppler?

Answer 18

Present end-diastolic flow (EDF)
Absent end-diastolic flow (AEDF)
Reversed end-diastolic flow (REDF)

Question 19

Describe umbilical artery absent end diastolic flow

Answer 19

in mid-late pregnancy usually occurs due to placental insufficiency

flow in umbilical artery should be in the FORWARD direction

If placental resistance increases, diastolic flow may reduce, later becoming absent + finally reverses

Question 20

What is the order of severity of umbilical artery doppler result?

Answer 20

Raised pulsitility index

Absent end diastolic flow (bad)

Reversed end diastolic flow (severe)

Question 21

What is the management of IUGR?

Answer 21

Conservative: stop smoking
Medical: low dose aspirin if indicated
Surgical: deliver if non reassuring fetal status/ maternal compromise