Foetal growth restriction Flashcards
Small for gestational age meaning
foetus with birth weight less than the 10th centile
(estimated foetal weight or abdominal circumference less than 10th centile)
What is severe small for gestational age?
estimated weight/abdominal circumference of foetus below 3rd centile
What is foetal growth restriction?
failure of the foetus to achieve its predetermined growth potential
What is the cut off for a low birth weight infant?
<2500g
What is ‘genuine’ foetal growth restriction?
attributed to an inadequate supply of nutrition to the foetus by a malfunctioning placenta
Types of foetal growth restriction
asymmetrical
symmetrical
What is symmetrical foetal growth restriction?
head size and trunk reduced in parallel
insult occurred early in antenatal period, during period of general organ growth
Causes of symmetrical growth restriction
congenital/chromosomal abnormalities
intrauterine infections
environmental factors
What is asymmetrical foetal growth restriction?
foetus responds to an inadequate supply of nutrition by adjusting in a way that maximises the chance of survival and involves redistribution of blood flow:
- more to brain, heart and adrenal glands
- less to liver and kidneys
- abdominal girth and fat stores reduced more than the head
normal head
small abdomen
Causes of asymmetrical growth restriction
pathology of later onset
- pre-eclampsia
- idiopathic foetal growth restriction
- essential hypertension
- maternal smoking
Maternal medical causes of foetal growth restriction
chronic hypertension
connective tissue disease
severe chronic infection
diabetes mellitus
anaemia
uterine abnormalities
maternal malignancy
pre-eclampsia
thrombophilic effects
Maternal behavioural causes of foetal growth restriction
smoking
low booking weight
poor nutrition
age >35 at delivery
alcohol
drugs
high altitude
social deprivation
Foetal causes of foetal growth restriction
multiple pregnancy
structural abnormality
chromosomal abnormalities
intrauterine (congenital) infection
inborn errors of metabolism
Placental causes of foetal growth restriction
impaired trophoblast invasion
partial abruption or infarction
chorioamnionitis
placental cysts
placenta praevia
Maternal factors associated with increased risk of foetal growth restriction
african american/indian/asian
nulliparity
BMI <20 or >25
maternal small for gestational age
daily vigorous exercise
short (<6mo) or long (>60mo) inter-pregnancy interval
maternal exposure to domestic violence during pregnancy
low maternal weight gain
maternal caffeine consumption >=300mg /day in 3rd trimester
singleton pregnancies following IVF
Sequelae of foetal growth restriction
hypoglycaemia
hypocalcaemia
hypothermia
polycythaemia
hyperbilirubinaemia
failure to thrive
learning difficulties
shirt stature
cerebral palsy
mental handicap
How is foetal growth restriction screened for?
abdominal palpation
symphysis-fundal height/abdominal girth
foetal biometry
amniotic fluid volume by US
umbilical doppler US
RCOG guidelines for symphysis-fundal height measurements
SFH measurement at every antenatal appt from 24 weeks
SFH plotted on customised chart not population-based chart
women with single SFH below 10th centile or slow or static growth by crossing centiles should be referred for US to measure foetal size
women in whom SFH is inaccurate (eg. large fibroids, BMI>35, hydramnios) should have serial assessment of foetal size on US
Management
foetal growth restriction >32 weeks gestation
increased foetal surveillance
delivery if evidence of acute or chronic foetal compromise
Management foetal growth restriction <32 weeks gestation
detailed USS to exclude foetal structural abnormality and to screen for markers or karyotypic abnormalities
karyotyping foetus via amniocentesis or chorionic villus sampling considered
foetal blood sampling for blood gases and investigation of viral infection
intensive and repeated foetal monitoring
How can you acutely assess foetal condition?
cardiotocography
foetal breathing movements
foetal body movements
How can you assess foetal condition more chronically?
liquor volume (volume of amniotic fluid)
foetal growth
How is foetal movement monitored?
mum report subjective change from pattern of movement
What is CTG?
cardiotocography
