Small for gestational age

Question 1

What is the definition of small for gestational age?

Answer 1

Fetus that measures below the 10th centile for their gestational age

Question 2

What measurements are used to assess fetal size on USS?

Answer 2

Estimated fetal weight
Fetal abdominal circumference

Question 3

What are customised growth charts?

Answer 3

Used to assess the size of fetus, based on mothers ethnic group, weight, height and parity

Question 4

What is severe SGA?

Answer 4

When fetus is below the 3rd centile for their gestational age

Question 5

What is a low birth weight?

Answer 5

Birth weight of less than 2500g

Question 6

What are risk factors of SGA?

Answer 6

previous SGA
obesity
smoking
diabetes
existing HTN
pre-eclampsia
multiple pregnancy
antepartum haemorrhage

Question 7

What 2 categories can SGA be divided into?

Answer 7

1. Constitutionally small → matches the mother and family members & growing appropriately on growth chart
2. Fetal growth restriction or intrauterine growth restriction → where there is a small fetus due to a pathology reducing the amount of nutrients & oxygen being delivered to the fetus

Question 8

What 2 categories can fetal growth restriction be divided into?

Answer 8

Placenta mediated growth restriction
Non-placenta mediated growth restriction

Question 9

What is placenta mediated growth restriction?

Answer 9

Refers to conditions that effects the transfer of nutrients across the placenta

Question 10

What are examples of placenta mediated growth restriction?

Answer 10

Pre-eclampsia
Maternal smoking/alcohol
Anaemia & malnutrition
Infection

Question 11

What are examples of non placenta mediated growth restriction?

Answer 11

Genetic abnormalities
Structural abnormalities
Fetal infection
Errors of metabolism

Question 12

What other signs indicate FGR over fetus being SGA?

Answer 12

Reduced amniotic fluids volume
Abnormal Doppler studies
Reduced fetal movements
Abnormal CTGs

Question 13

What are short term complications of fetal growth restriction?

Answer 13

Fetal death or stillbirth
Birth asphyxia
Neonatal hypothermia
Neonatal hypoglycaemia

Question 14

What are growth restricted babies at increased risk of?

Answer 14

CVD
Type 2 diabetes
obesity
mood & behavioural problems

Question 15

How do you measure growth restriction?

Answer 15

Low risk women have monitoring of symphysis fundal height at every antenatal appointment from 24 weeks onwards to identify potential SGA
It is plotted on a customised growth chart to assess the appropriate size for the individual woman
If it is less than 10th centile, women are booked for serial growth scans with umbilical artery doppler

Question 16

When else are women booked for serial growth scans?

Answer 16

Three or more minor risk factors
One or more major risk factors
Issues with measuring the symphysis fundal height

Question 17

How are women closely monitored?

Answer 17

Estimated fetal weight and abdominal circumference to determine growth velocity
Umbilical artery pulsatility index to measure flow through umbilical artery
Amniotic fluid volume

Question 18

What are the critical management steps?

Answer 18

1. Identifying those at risk
2. Aspirin given to those at risk of pre-eclampsia - 12 weeks (before) to 6 weeks postpartum
3. Treating modifiable risk factors
4. Serial growth scans to monitor growth
5. Early delivery where growth is static

Question 19

What investigations are done?

Answer 19

Blood pressure & urine dipstick for pre-eclampsia
Uterine artery doppler scanning
Detailed fetal anatomy by fetal medicine
Karyotyping for chromosomal abnormalities
Testing for infections