Small for Gestational Age Flashcards
Small for Gestational Age
Fetus that measures below the 10th centile for their gestational age
How is fetal size assessed
USS:
- Estimated fetal weight (EFW)
- Fetal abdominal circumference (AC)
How are growth charts standardised
Different growth charts used based on the mother’s:
Ethnic group
Weight
Height
Parity
Severe Small for gestational age
Below the 3rd centile for their gestational age
Low birth weight
< 2500g
Causes of small for gestation age
Constitutionally small
Fetal growth restriction (FGR) - intrauterine growth restriction (IUGR)
Constitutionally small
Matching the mother and others in the family, and growing appropriately on the growth chart
Intrauterine growth restriction
Small fetus (or a fetus that is not growing as expected) due to a pathology reducing the amount of nutrients and oxygen being delivered to the fetus through the placenta
Causes of fetal growth restriction
- Placenta mediated growth restriction
- Non-placenta mediated growth restriction
Non-placenta mediated growth restriction
Baby is small due to a genetic or structural abnormality
Causes of placenta mediated growth restriction
Conditions that affect the transfer of nutrients across the placenta
- Idiopathic
- Pre-eclampsia
- Maternal smoking or alcohol
- Anaemia
- Malnutrition
- Infection
- Maternal health conditions
Causes of non-placenta medicated growth restriction
Genetic abnormalities
Structural abnormalities
Fetal infection
Errors of metabolism
Signs of fetal growth restriction
Reduced amniotic fluid volume
Abnormal Doppler studies
Reduced fetal movements
Abnormal CTGs
Complications of fetal growth restriction
Fetal death or stillbirth
Birth asphyxia
Neonatal hypothermia
Neonatal hypoglycaemia
Long term complications of fetal growth restriction
Increased risk of:
- Cardiovascular disease, particularly HTN
- Type 2 diabetes
- Obesity
- Mood and behavioural problems
Risk factors for SGA
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
Monitoring of SGA
Low-risk women - monitoring of the symphysis fundal height (SFH) at every antenatal appointment from 24 weeks onwards to identify potential SGA.
If the symphysis fundal height is < 10th centile, serial growth scans with umbilical artery doppler.
Which women are booked for serial growth scans with umbilical artery doppler
- 3+ minor risk factors
- 1+ major risk factors
- Issues with measuring the symphysis fundal height (e.g. large fibroids or BMI > 35)
What do serial ultrasound scans measure
- Estimated fetal weight (EFW) and abdominal circumference (AC) to determine the growth velocity
- Umbilical arterial pulsatility index (UA-PI) to measure flow through the umbilical artery
- Amniotic fluid volume
Management of SGA
- Identifying those at risk of SGA
- Aspirin if at risk of pre-eclampsia
- Treating modifiable risk factors (e.g. stop smoking)
- Early delivery - if growth is static, or there are other concerns
What investigations are done for SGA
Blood pressure and urine dipstick for pre-eclampsia
Uterine artery doppler scanning
Detailed fetal anatomy scan by fetal medicine
Karyotyping for chromosomal abnormalities
Testing for infections (e.g. toxoplasmosis, cytomegalovirus, syphilis and malaria)
When is early delivery considered in SGA
When growth is static on the growth charts, or other problems are identified (e.g. abnormal Doppler results)
Why may early delivery occur
Reduce the risk of stillbirth
What is given when planning an early delivery
Corticosteroids, particularly when delivered by caesarean section.
Paediatricians involvement at birth - help with neonatal resuscitation and management if required
