Fetal Growth Restriction Flashcards
Define fetal growth restriction
Failure of the fetus to achieve its predetermined growth potential
How is small gestational age defined?
Birth weight below 10th centile
What is associated with an increased risk of perinatal morbidity and mortality?
Low birth weight
Which three things are associated with similar pathologies?
Low birth weight
Fetal growth restriction
Preterm delivery
Describe the relationship between low birth weight neonates and growth restricted neonates
Not all low birth weight neonates are growth restricted
What are the most commonly employed centiles for small gestational age?
Tenth
Fifth
Third
Which centile is most SPECIFIC and what does this mean?
Third centile
Good at identifying people without the disease
Which centile is the most SENSITIVE and what does this mean?
Tenth centile
Good at correctly identifying babies with FGR
What is required for the diagnosis of fetal growth restriction?
Close observation over time
What is the consequence of IUGR for subsequent babies?
Increased risk of IUGR and IUD (intrauterine death) in subsequent pregnancies
What are the short term consequences of LBW/FGR/prematurity for the fetus?
Respiratory distress (lack of surfactant) Intravascular haemorrhage Sepsis Hypoglycaemia Necrotising enterocolitis Jaundice Electrolyte imbalance
What are the medium term consequences of LBW/FGR/prematurity for the fetus?
Respiratory problems
Development delay
Special needs schooling
What are the long term consequences of LBW/FGR/prematurity for the fetus?
Fetal programming
List four causes of babies being ‘small for gestational age’
Dating problem (growth continues, dopplers and fluid are normal but we’ve got the date wrong)
May just be a normally small baby
Fetal abnormality/infection (5%)
Placental insufficiency (20%)
What are the consequences of an insufficient placenta?
Reduced abdominal circumference Reduced femur length Reduced amniotic fluid Baby pees less (conserves energy, moves less) Deranged dopplers
Give some maternal medical factors related to blood which are associated with FGR and SGA
Chronic HTN
Pre-eclampsia
Anaemia
Thrombophilic defects
Give some maternal medical factors related to infection/inflammation/the immune system which are associated with FGR and SGA
Malignancy Severe chronic infection DM Connective tissue diseases Uterine abnormalities
Give some maternal behavioural factors associated with FGR and SGA
Smoking Alcohol Drugs Social deprivation Poor nutrition Age (<16 or >35) Low weight (<50kg) High altitude
Give some fetal factors associated with FGR and SGA
Multiple pregnancies Structural abnormalities Chromosomal abnormalities IU infection Inborn errors of metabolism
Give some placental factors associated with FGR and SGA
Impaired trophoblast invasion Partial abruption or infarction Chorioamnionitis Placental cysts Placenta praevia
What is placenta praevia?
When the placenta actually blocks the neck of the uterus, meaning that the baby can’t get out
How long does placentation last for?
10-12 weeks
Give three key features of the placenta
Maintains immunological distance between mother and fetus
Acts as a transient hypothalamo-pituitary gonadal axis
Responsible for exchange of nutrients, gases and metabolic wastes
As a special endocrine organ, name two things which the placenta produces
Protein peptides
Steroid hormones
Compare the placental changes in pre-eclampsia and normotensive mothers
Normotensive:
Spiral arteries lose muscular strength -> widening of arteries -> increased blood flow
Pre-eclampsia:
Spiral arteries remain narrow, under high pressure -> reduced and insufficient blood flow to baby
Define pre-eclampsia and state when it arises and resolves
De novo multisystem disease that manifests as hypertension and proteinuria
Starts: after 20th week
Resolves by 6th week post partum
How common is HTN and pre-eclampsia in pregnancies?
10% of all pregnancies, but only 1-2% is severe form
Give the measurements for proteinuria in pre-eclampsia
> 0.3g/24hr
Protein-creatinine ratio>30
Give the classifications of pre-eclampsia
Mild (140-149/90-99mmHg) Moderate (150-159/100-109mmHg)
Severe (≥160/110mmHg)
Generally speaking, which two reasons would require extra foetal growth monitoring?
Those where the mother has a history of obstetric problems
Concerns in the current pregnancy
State for things which constitute a poor obstetric history and therefore require the new fetus to have extra growth monitoring
Previous stillbirth
Previous FGR
Placental abruption
Previous maternal HTN
State four factors about the current pregnancy which may warrant extra fetal growth monitoring
Abnormal serum biochemistry
Reduced SFH
Maternal systemic disease
Antepartum haemorrhage
Give an abnormal serum biochemistry and its indication
Low PAPP-A <0.03 MOM
PAPP-A = pregnancy associated plasma protein A
Note: PAPP-A is low in Down syndrome
Give examples of systemic maternal disease
HTN
Coagulation
Renal problems
What is antepartum haemorrhage?
Bleeding from into the genital tract before giving birth
What can be used to assess uterine arteries?
Uterine artery doppler screen
What are the two things which result from hypoxia to the fetus?
CNS dysfunction
Stimulation of chemoreceptors in aorta
What are the consequences of CNS dysfunction following hypoxia to the fetus?
Poor tone
Altered breathing
Altered movement patterns
Changes in heart rate patterns
What are the consequences of aortic chemoreceptor stimulation following hypoxia to the fetus?
Redistribution of cardiac output by:
increasing blood flow (to brain, heart and adrenals) and reducing blood flow (to lungs, kidneys and gut)
Which areas of the fetus get increased blood flow following hypoxia?
Brain
Heart
Adrenals
Which areas of the fetus get reduced blood flow following hypoxia?
Lungs
Kidneys (hence they pee less)
Gut
What do you see in a doppler of the middle cerebral artery of the fetus during hypoxia?
Low resistance blood flow (more frequent triangles)
Where does 25% of the blood flowing through the umbilical vein go to and affect?
Ductus venosus
Liver
Contributes to abdominal circumference growth
Which part of the heart is dominant in foetuses?
Right ventricle
Where does the blood go from the right side of the heart?
To the left side via foramen ovale
What changes do you seen in venous doppler in FGR?
Baby more acidotic, therefore you see an abnormal venous doppler
How can mothers help to monitor their fetal wellbeing?
By monitoring the time taken each day to feel TEN fetal kicks
What do you do if the mother reports a reduction in or absence of fetal movements?
Do a cardiotocography (CTG) and/or ultrasound
Describe the general principles of management of FGR pregnancies
‘Index’ pregnancy (CTG, serial fetal biometry, fetal doppler, BPP)
Ultrasound screen at 24w for ‘at risk’ pregnancies
Deliver at or after 28w, or after 500g (C-section for compromised foetuses)
What is BPP?
Fetal biophysical profile
When would you deliver a baby before it is due?
If there is evidence of fetal compromise on CTGs
Abnormal Dopplers
Abnormal ultrasounds
Maternal compromise
What should be administered if gestation is prior to 36 weeks?
Corticosteroids to induce surfactant production to help the baby breatheee
What will affect the mode of delivery?
Gestation of the pregnancy Condition of the pregnancy Cervix condition Presentation of fetus Other factors e.g. oligohydramnios / cord compression
Compare early IUGR to late IUGR
Low IUGR:
Low incidence
High correlation to maternal disease e.g. pre-eclampsia
Difficult to balance risk of severe prematurity and morbidity with risk of IUD
Late IUGR:
More common (5-7%)
Rarely correlated with Pre-eclampsia
Difficult to differentiate from constitutionally SGA
Easier to manage by delivery but difficult to tell when and how it should be done
Pre-eclampsia is associated with IUGR at which stage?
Early IUGR
