IUGR/Small for gestational age Flashcards
What is “small for gestational age”?
what is severe?
infant with birth weight <10th centile for its gestational age
severe = <3rd centile
What is foetal small for gestational age vs foetal growth restriction?
foetal SGA = est. foetal weight or abdo circumference <10th centile
vs
foetal growth restriction = pathological process that restricted genetc growth potential –> px: can be feautures of foetal compromise including
- reduced liquor volume or
- abdominal doppler studies
TF those who are small for gestational age could be constitutionally small (small at all stages, growth follows centiles, ~60%) or has IGUR due to pathology….
What impact does SGA have on a childs size for when they become an adult?
- 90% SGA catch up growth in 1st 2yrs,
- however as adults they are on average 1 SD shorter than the mean adult height
- May be an association between SGA & adult risk of coronary heart disease & obesity
What do these things have in common?
- Maternal age 35+ y/o
- smoker 1-10/day
- nulliparity
- BMI <20 or 25-34.9
- IVF singleton
- previous pre-E
- pregnancy interval <6m or >60months (5yrs)
- low fruit intake pre-pregnancy
they are all minor risk factors for the babies being small for gestational age
What do these things have in common?
- maternal age >40
- smoker 11+/day
- previous stillbirth
- cocaine use
- daily vigorous exercise
- maternal disese (HTN, renal impairment, DM with vascular disease, anti-phospholipid syndrome)
- heavy bleeding
- low PAPP-A
These are MAJOR risk factors for small for gestational age
+ also having a preveious SGA baby
+ maternal/paternal SGA
(was just too obvious to have on the front)
If foetal growth restriction is a pathological process that has restricted genetic growth proential and can present with features of foetal compromise inc. reduced liqor volume or abdominal doppler studies.
How can you tell this?
the baby is small for their gestational age and appears thin and malnourished
something has prevented the foetus from reaching its genetic growth potential
What maternal factors can prevent the foetus from reaching its genetic growth potential? (e.g. IUGR)
Maternal
- undernutrition
- RF: BMI >35
- maternal hypoxia
- cyanotic heart disease
- chronic respiratory disease
- drugs
- alcohol
- cigarettes - 1-10= minor RF
- illicit / drug abuse esp. cocaine!
RF: also maternal age over 35 is minor RF, >40 is major, 1st preg is minor RF, low fruit intake minor too.
What placental factors can prevent the foetus from reaching its genetic growth potential? (e.g. IUGR)
Placental factors:
- Reduced vascular supply
- PET, HTN,
- diabetes, renal disease
- Thrombosis or infarction
- sickle cell disease; a
- Anti-phospholipid syndrome
- Sharing
- i.e. multiple foetuses.
What foetal factors can prevent the foetus from reaching its genetic growth potential? (e.g. IUGR)
Foetal factors of IUGR
- Constitutional (normal)
- Some chromosomal disorders or syndromes
- e.g. Edwards (trisomy 18)
- Structural malformation
- Error in metabolism
- Congenital infection
- e.g. CMV
What are the 2 types of intrauterine growth restriction?
Asymmetrical IUGR (most common)
- caused by utero-placental insufficiency late in pregnancy e.g. PET –> IUGR
- the babys weight or heights is < than head circumference because the brain being vital organ is spared at the expcense of liver glycogen stores and subcut fat
- the infants rapidly put on weight after birth
symmetrical IUGR
- caused by prolonged period of poor intrauterine growth
- normally due to foetal factors –> chromosomes, constitutionally small, metabolism error,
- the head circumference and body weight lie in similar centiles
- these infants are likely to remain small
What investigations help investigate further asymmetrical IUGR vs Symmetrical IUGR? / causes of IUGR?
- USS
- diagnosis & surveillance in utero
- estimated foetal weight
- head circumference: abdo circumference
- identifies brain sparing, amniotic fluid volume - placental insufficiency
- diagnosis & surveillance in utero
- detailed foetal anatomical survey
- uterine artery doppler
- karyotyping
- screening for infections including CMV, toxoplasmosis, syphylis, malaria
- screen for PET
Why may a baby with IUGR need to be born by elective C-section?
intrauterine hypoxia and death and perinatal asphyxia are complications of IUGR
these are the commonest cause of stillbirth
What do these neonatal conditions have in common?
- Lung problems:
- Birth asphyxia
- Meconium aspiration
- Persistent pulmonary HTN
- Pulmonary haemorrhage
- Opthalm: Retinopathy of prematurity
- GI: Necrotising enterocolitis
- Metabolic/vitals
- Hypothermia, Hypoglycaemia, Hypocalcaemia.
- Blood: Polycythaemia.
they are complications of IUGR!
NB: they basically look like all the problems you get with prematurity e.g. foetus not quite ready/developed
eg:
- Hypothermia –> due to relatively large surface area compared to mass.
- Hypoglycaemia –> due to lack of fat and glycogen stores.
What conditions is there evidence for that IUGR leads to in later life?
- CVS RF’s:
- Hypertension
- Diabetes mellitus type 2
- Coronary heart disease
- Stroke
- Cerebral palsy
- hormonal?
- Obesity
- Precocious puberty (early)
- Psych:
- Depression Alzheimer’s , Behavioural problems
- Oncological:
- Breast, ovarian, colon, lung & blood
What 2 ways are there to prevent IUGR?
- women with PET -
- take 75mg aspirin from 12wks until delivery
- modify other risk factors
- STOP smoking
- (illicit drugs, alcohol, diabetes control too etc)
What surveillance is done for women who are low risk for IUGR?
- measure symphysis fundal height
- (e.g. every woman gets these)
what surveillance for IUGR is done for women with >3 minor risk factors?
‘Minor risk factors’:
- 1st pregnancy,
- IVF singleton pregnancy,
- low fruit intake,
- smoker 1-10/day,
- age 35-39yrs
- uterine artery doppler at 20/40wks
What surveilllance for IUGR is done for women at high risk?
‘High risk pregnancies’:
- mum >40yrs,
- BMI >35,
- multiple pregnancy,
- previous IUGR,
- PET, (take 75mg aspirin from 12wks–.delivery)
- maternal medical disorders,
- smoking & drug abuse (especially cocaine),
- anti-phospholipid syndrome
serial US & uterine artery doppler (UAD) in T3 … looking at:
- Foetal growth
- Liquor volume
- Umbilical artery flow
overall what tests are useful for surveillance of IUGR in pregnancy?
Other tests useful in surveillance include:
- symphysis fundal height (SFH),
- amniotic fluid volume.
- middle cerebral artery (MCA)
- Doppler, ductus venosus (DV) Doppler,
- cardiotocography (CTG)
when can induction of labour be offered (for IUGR?)?
at 37 weeks
+ normal UAD
If a pregnant lady has a baby <37 weeks old and an absent/reverse end diastolic flow on doppler, what should be done?
give antenatal steroids
c-section
if a pregnancy lady has a baby w/IUGR but <37 weeks and an abnormal uterine artery doppler or middle cerebral artery doppler what should be done?
can offer induction or c-section
give antenatal steroids until 35+6 weeks
When should a pregnant lady with IUGR be given steroids from?
+ antenatal maternal steroids 26-36wks
- 2x injections betamethasone or dexamethasone
- 12mg 12-24hrs apart
- reduces risk IVH, PDA, RDS, NEC, foetal death
Before induction/c-section what else besides steroids should be given?
MgSO4
- from 24-30wks
- to protect against cerebral palsy
- (IV if delivery planned in next 12hrs)
MgSO4 –>improves blood flow & reduces hypoxic damage at time of delivery in premature babies
IUGR is associated with neonatal hypoglycaemia
what other conditions are as well?
- maternal diabetes mellitus*
- prematurity
- hypothermia
- neonatal sepsis
- inborn errors of metabolism
- nesidioblastosis (excessive insulin production by pancreatic beta cells)
- Beckwith-Wiedemann syndrome (as hyperinsulinism is a syx)
when is neonatal transient hypoglycaemia common/normal for?
the first few hours to days
babies of diabetic mothers are commenced on a hypoglycaemia protocol. When can this be stopped?
NB: <4 is hypoglycaemia but syx not until <3mmol and
<2.2mmol/L is serious
TF babies of diabetic mothers can stop the hypoglycaemia protocol once they have:
- at least 3x blood glucose values >2.5mmol/L
- & are feeding appropriately
