Foetal growth restriction Flashcards
Definition of small for gestational age (SGA)
- Abdominal circumference (AC) or estimated foetal weight (EFW) less than the 10th centile
- Normal doppler scan - Sufficient blood flow
Definition of severe small for gestational age (SGA)
AC or EFW < 3rd centile
Definition of foetal growth restriction (FGR)
- Failure of the foetus to attain their growth potential
- All babies will be below 3rd centile or below 10th with placental dysfunction
- Abnormal doppler - Blood flow insufficient
Definition of low brith weight (LBW)
Any baby born with a weight of 2.5kg (5.5lbs) at any gestation
What are some antenatal risks of FGR and SGA
hypoxia and stillbirth
Post-natal risks of FGR and SGA
- Hypoglycaemia
- Asphyxia
- Hypothermia
- Polycythaemia
- Hyperbilirubinaemia
- Abnormal neurodevelopment
- Complications of prematurity
Maternal causes of SGA
- Lifestyle - Smoking, alcohol, drugs
- Very low or high BMI
- Age
- Maternal diseases - E.g. hypertension, renal disease
Placental causes of SGA
- Infarctions
- Abruptions (Antepartum haemorrhage - APH)
- Association with hypertensive diseases (E.g. pre-eclampsia)
Foetal causes of SGA
- Infection - E.g. Rubella, CMV, Toxoplasmosis
- Congenital abnormalities
- Chromosomal abnormalities
Risk factors for SGA
- Maternal age > 40
- Nulliparity
- Low or High BMI (<19, >35)
- Maternal substance use
- IVF pregnancy
- Daily vigorous exercise
- Previous SGA baby or stillbirth
- Maternal SGA
- Echogenic bowel
- Fibroids
- Conditions such as chronic HTN, diabetes with vascular disease, renal impairment, antiphospholipid syndrome, paternal SGA
What are some ways of preventing SGA
- Aspirin for those at risk of pre-eclampsia
- Vitamin D supplementation
- Smoking cessation (Cessation before 15 weeks reduces risk to same as a non-smoker)
- Drug service input
- LMWH in antiphospholipid syndrome
What is SFH
Symphysis-Fundal height
What investigations are required in those at moderate risk of SGA
Serial USS from 32 weeks every 4 weeks until delivery
What investigations are required in those at high risk of SGA
Uterine artery doppler then serial USS (Dates depend on uterine artery doppler results)
When is SFH usually measured?
At every appointment from 24 weeks
When is growth scanning indicated in SFH measurement
If SFH growth chart is below 10th gentile, is static or the curve crosses centiles
Advantages of SFH measurement
- Cheap
- Easy and available
- Better continuity of care
What 3 measurements are done on USS fro foetal growth
- Measurement of abdominal circumference (AC)
- Measurement of head circumference
- Measurement of femur length
What is EFW?
Estimated foetal weight (EFW)
What is liquor?
Fluid surrounding the baby
What produces the liquor
Placenta and baby
What are some measurements of liquor volume?
Deepest vertical pool (DVP)
Amniotic Fluid Index (AFI)
Normal DVP
2-10cm
What are some forms of doppler scan done in assessment of foetal growth
Umbilical artery doppler
Middle cerebral artery doppler
Ductus venosus doppler
Characteristics of umbilical artery doppler
The umbilical artery should be low resistance with forward flow throughout the maternal cardiac cycle
Pulsatility index can be measures, which reduces as gestation advances
<1.4 is always normal
This flow can be absent or reversed
What is shown in a, b and c
- Normal blood flow
- Absent end-diastolic flow
- Reversed end-diastolic flow
Characteristics of middle cerebral artery doppler
This indicates brain perfusion
There will be a reduced pulsatility index in a compromised foetus
There is increased peak systolic velocity in foetal anaemia
This is useful as an additional marker for SGA/FGR after 32 weeks
Characteristics of ductus venosus doppler
This is a direct reflection of foetal heart function
This will show A-waves:
- Flow during atrial contraction of the foetal heart
- Becomes progressively deeper as foetal condition worsens
This is used to time delivery and is particularly useful in preterm FGR
Management of AC/EFW in gentile 3-10
- Fortnightly scans for foetal growth, DVP and dopplers
- Esnure regular BP and urine check
- Advice on symptoms of pre-eclampsia
- Advice about increased risk of stillbirth and to report reduced movements immediately
- Offer induction of labour at 39 weeks and aim to delivery by 39+6
Management of AC/EFW gentile < 3
- Once weekly monitoring of foetal dopplers
- Computerised CTG
- Monitor for pre-eclampsia
- Clear advice on stillbirth risk
- Deliver at 37 weeks, no later than 37+6
