Introduction
The administration of antenatal corticosteroids (ACS) to improve
neonatal outcomes after preterm birth is considered one of the most
important interventions in perinatal medicine.1 The
short-term benefits of administering ACS prior to elective caesarean
section even at term gestations up to 38+6 weeks in
reducing respiratory morbidity have been reported.2-4Diabetes, both gestational and pre-gestational, is the most common
medical condition experienced in pregnancy and the rates of both
gestational diabetes and Type 2 diabetes are
increasing.5,6 Maternal diabetes increases the risk of
caesarean section and birth at earlier gestations.7,8Interestingly, the majority of studies examining the impact of ACS on
neonatal outcome have excluded women with diabetes or have included only
an extremely small number of women. Therefore, it would be inappropriate
to extrapolate the results of these studies to women with
diabetes.2-4,9,10 This is despite the well-known risks
of pre-gestational diabetes on obstetric outcomes including higher rates
of preterm and early term caesarean sections and increased risks of
neonatal respiratory distress syndrome.7,11 Caesarean
section itself, remains an independent risk factor for respiratory
morbidity.3,12
Uncertainty remains regarding the role of ACS for women with diabetes
who are giving birth by elective caesarean section prior to
39+0 weeks gestation. In the light of the paucity of
evidence, the Australian and New Zealand Clinical Practice guidelines
specifically state that “there is insufficient evidence currently to
make a recommendation for the use of ACS prior to planned caesarean
section at term (> 37+0 weeks’ gestation)
for women with diabetes in pregnancy”.13 The American
College of Obstetricians and Gynecologists acknowledges the lack of
evidence in this context and does not provide specific recommendations
regarding the use of ACS in this population during the late pre-term or
early term period,14 while the Royal College of
Obstetricians and Gynaecologists in the United Kingdom had previously
recommended ACS for all women prior to Caesarean birth but have
subsequently withdrawn this guideline.15
This retrospective study investigated all women with pre-existing
diabetes mellitus who gave birth to a singleton infant via elective
caesarean section between 36+0 and
38+6 weeks gestation between 1 January 2011 and 31
December 2019 at two academic centres in Victoria, Australia.
The primary aim was to ascertain whether the use of ACS (betamethasone
11.4 mg, 2 injections 24 hours apart) within 7 days prior to birth by
elective caesarean section reduces the incidence of neonatal respiratory
distress. Secondary neonatal outcomes, including neonatal nursery care,
sepsis and hypoglycaemia were also evaluated.