Antenatal - small for gestational age Flashcards
what is small for gestational age defined as?
fetus that measures below the 10th centile for gestational age
what 2 measurements are used to assess fetal size?
estimated fetal weight (EFW)
fetal abdominal circumference (AC)
mothers have customised growth charts generated to assess the size of the fetus. what are the growth charts based on?
mothers ethnic group, weight, height and parity
what is considered to be severe small for gestational age (SGA)
when the fetus is below the 3rd centile for their gestational age
low birth weight is defined as what
birth weight of less than 2500g
what are the 2 categories of small for gestational age?
Constitutionally small - matching the mother and others in the family, and growing appropriately on the growth chart
fetal growth restriction aka intrauterine growth restriction - small fetus due to pathology reducing the amount of nutrients and oxygen being delivered to the fetus through the placenta
how can the causes of fetal growth restriction be divided into categories?
placenta mediated growth restriction - large head in comparison to body
non-placenta mediated growth restriction - usually due to genetic or structural abnormality and babys head is in proportion to body
what are some placenta mediated growth restriction causes (conditions that affect the transfer of nutrients across the placenta)
idiopathic
pre-eclampsia
maternal smoking
maternal alcohol
anaemia
malnutrition
infections
maternal health conditions
what are some non-placenta mediated growth restriction causes
- genetic abnormalities
- structural abnormalities
- fetal infection
- errors of metabolism
what are some other signs that would indicate FGR other than being SGA?
- reduced amniotic fluid volume
- abnormal doppler studies
- reduced fetal movements
- abnormal CTGs
What are some short term complications of fetal growth restriction?
- fetal death or stillbirth
- birth asphyxia
- neonatal hypothermia
- neonatal hypoglycaemia
what do growth restricted babies have a long term increased risk of?
- Cardiovascular disease - HTN, coronary artery problems
- T2DM
- Obesity
- Mood and behavioural problems
- autoimmune thyroid problems
what are some risk factors for Small for Gestational Age?
- Previous SGA baby
- Obesity
- Smoking
- Diabetes
- Existing hypertension
- Pre-eclampsia
- Older mother (over 35 years)
- Multiple pregnancy
- Low pregnancy‑associated plasma protein‑A (PAPPA)
- Antepartum haemorrhage
- Antiphospholipid syndrome
- malnutrition
- substance misuse
- domestic violence
how are women assessed at the booking clinic for SGA?
women are assessed for risk factors for SGA and then monitored accordingly. RCOG lists major and minor risk factors
how are women low-risk for SGA monitored?
have symphysis fundal height measured at every antenatal appointment from 24 weeks onwards and this is plotted on a customised growth chart to asses the appropriate size for the individual woman.
if the SFH is less than the 10th centile women are booked for serial growth scans with umbilical artery doppler
