TOG -The role of antenatal corticosteroids in improving neonatal outcomes. August 2021

Question 1

Which pneumocytes do antenatal corticosteroids affect

Answer 1

Type II pneumocytes

Question 2

By which mechanism is it thought that antenatal corticosteroids (ACS) reduce intraventricular haemorrhage?

Answer 2

glucocorticoid receptors (GR) are expressed in numerous fetal tissues including the brain, lungs and placenta. GR signalling pathways are important for the stabilisation of vascular endothelial cells.

Question 3

Which placental enzyme limits the transfer of endogenous glucocorticoids, (cortisone and corticosterone).

Answer 3

11B-HSD2 (11B-hydroxysteroid dehydrogenase type 2).
Synthetic glucocorticoids (dexamethasone and betamethasone) are able to bypass this barrier.

Question 4

What have animal studies demonstrated regarding 11b-HSD2 expression towards parturition.

Answer 4

There is a notable reduction in 11BHSD2 expression allowing more maternal glucocorticoid to reach the fetus.

Question 5

What is the effect of ACS on neuro stem/progenitor cells?

Answer 5

They exert antiproliferative effects on neuro stem/progenitor cells that may contribute to long term behavioural and cognitive effects in infants exposed to ACS.

Question 6

Cochrane review evidence supporting use of ACS

Answer 6

Reduction in :
RDS - RR 0.66,
Need for mech ventilation - RR 0.68,
Neonatal death - RR 0.69
NEC - RR 0.5
IVH - RR 0.55

Question 7

Further evidence of potential harm has been demonstrated in samples taken at autopsy from preterm infants 24-32/40 who died within 4 days of life and were exposed to ACS.
These samples demonstrated a significantly lower density of neurons in the hippocampus of the treated neonates.

Answer 7

.

Question 8

potential risks especially in those delivered at term and exposed to ACS in utero in a retrospective study.

Answer 8

More likely to be referred for assessment of hearing,visual, or cognitive problems.

Question 9

Repeat ACS may improve short term outcomes, namely RDS but this may be at the expense of…

Answer 9

neurological development in childhood

Question 10

Those particularly vulnerable the side effects of ACS are those infants who had…

Answer 10

single or repeat courses of ACS in utero but then delivered at term.

Question 11

What percentage of preterm births are “medically indicated”.

Answer 11

30-35%

Question 12

Late preterm ACS 34-36+5 may improve short term respiratory complications, but their use may contribute to an increased risk of

Answer 12

neonatal hypogylcaemia.
Hypoglycaemia may in turn affect long term development but requires longer follow up for confirmation.