8.9 Small for Gestational Age Flashcards
Define small for gestational age (SGA) and how it is assed?
below 10th centile for gestational age.
Two measurements on US:
- estimated fetal weight (EFW)
- fetal abdominal circumference (AC)
Customised growth charts based on mothers:
weight; height; parity; ethnic group
When is it severe SGA?
when foetus is below 3rd centile for their GA
What weight is defined as “low birth weight”?
weight of less than 2500g
Two categories of SGA?
- constitutionally small (small mother and family so is appropriate)
- fetal growth restriction (FGR) aka intrauterine growth restriction (IUGR)
What is the difference between SGA and FGR?
SGA is small
FGR is when there is SGA due to a pathology limiting nutrients and O2
What two categories of causes of FGR are there?
- placenta mediated growth restriction
- non-placenta mediated growth restriction (genetic or structural)
8 causes of placental mediated FGR / IUGR?
- pre-eclampsia
- maternal smoking
- maternal alcohol
- anaemia
- malnutrition
- infection
- maternal health conditions
- idiopathic (unknown)
(transfer of nutrients across placenta is affected)
4 causes of non-placenta mediated FGR?
- genetic abnormalities
- structural abnormalities
- fetal infection
- errors in metabolism
Other than SGA what other sign of FGR might there be?
- reduced amniotic fluid volume
- abnormal doppler
- reduced fetal movements
- abnormal CTGs
Short term complications of FGR?
- fetal death or stillbirth
- birth asphyxia
- neonatal hypothermia
- neonatal hypoglycaemia
Longterm complications of FGR?
- cardiovascular disease esp hypertension
- T2DM
- obesity
- mood and behaviour problems
Risk factors for FGR?
- previous SGA baby
- obesity
- smoking
- diabetes
- HTN
- pre-eclampsia
- over 35 yrs
- multiple pregnancy
- low PAPPA
- antepartum haemorrhage
- antiphospholipid syndrome
(minor and major ones according to RCOG)
What does RCOG recommend for women at low risk fo FGR?
Measure symphysis fundal height (SFH) at every antenatal appointment from 24 weeks to identify potential SGA.
(plot on customised chart)
When would women be booked for serial growth scan with umbilical artery doppler?
- SFH is <10th centile
- three or more minor risk factors
- one or more major risk factor
- issues measuring SFH eg BMI or fibroids
(check RCOG green top guidelines for minor and major risk factors)
So the high risk of FGR or SGA indicates serial growth scan with umbilical artery doppler, what does this measure?
- estimated fetal weight (EFW) and abdo circumference (AC)
- umbilical artery pulsatility index UA-PI
- amniotic fluid volume
(frequency etc of scan vary on local guidelines)
