Z - archive - C*STEROID information for clinicians and midwives

Can we safely reduce the risk of breathing problems for newborn babies by giving corticosteroid injections to their mothers before a planned caesarean section?


The C*STEROID trial is a randomised controlled trial of antenatal corticosteroids prior to planned CS at 35+0 to 39+6 weeks.

The aim of the C*STEROID Trial is to find out whether giving mothers corticosteroid injections before having a planned CS from 35+0 to 39+6 weeks of pregnancy will safely reduce the risk of short term breathing problems for babies.

The rate of birth by planned, also referred to as elective and pre-labour, CS continues to rise each year and now accounts for more than one in ten births and 7500 babies born in New Zealand each year. Compared to vaginal birth, CS poses additional risks to baby. Most specifically respiratory morbidity, often referred to as respiratory distress syndrome (RDS) and transient tachypnoea of the newborn (TTN). Term and late preterm babies rarely die from this, but the need for respiratory support requires neonatal unit (NNU) admission and separates mother and baby.

Maternal administration of corticosteroids prior to preterm birth at <35+0 weeks gestation provides protection against RDS, perinatal death and neonatal adverse outcomes with little or no evidence of later harm. What is less clear is if their use at gestational ages ≥35 weeks, and specifically prior to planned CS, provides benefit without harm.

Corticosteroids before late preterm birth may be associated with an increased risk of neonatal hypoglycaemia. Neonatal hypoglycaemia in ‘at risk’ infants born after 35+0 weeks is associated with later developmental delay.

We don’t know if corticosteroid use before CS at late preterm and term gestational ages reduces neonatal respiratory morbidity, and/or increases neonatal hypoglycaemia or what the longer term effects may be.

The C*STEROID Trial will determine whether antenatal administration of corticosteroids prior to planned CS at 35+0 to 39+6 weeks provides benefit without harm. We will assess neonatal respiratory morbidity and neonatal hypoglycaemia and aim to assess impact on later childhood development.


Inclusion criteria

  • Planned CS at 35+0 to 39+6 weeks
  • >24 hours & <7 days until planned birth
  • Singleton or twin pregnancy with a live fetus

Exclusion criteria

  • Diabetes (pre-existing or gestational)
  • Major fetal anomaly
  • Prior corticosteroid use in pregnancy (intramuscular corticosteroid use for fetal lung maturity)
  • Prior enrolment in the C*STEROID Feasibility Study or C*STEROID Trial, in a previous pregnancy

What does C*STEROID involve for women?

The C*STEROID research team and local clinicians will approach women and coordinate the study procedures:

  • Invitation to participate and obtaining consent
  • Questionnaires at study entry and 6 weeks after delivery
  • Two betamethasone or placebo injections >24 hours and < 7 days prior to planned CS given 24 hours apart
  • Neonatal blood glucose monitoring in the first 12 hours

The remainder of clinical care will continue as usual.



The C*STEROID Clinical Research Coordinators can be contacted by email csteroid@auckland.ac.nz or phone 022 4311 988.

For urgent clinical enquiries contact the Principal Investigator, Professor Katie Groom, k.groom@auckland.ac.nz.