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in the United Kingdom had previously recommended ACS for all women prior to Caesarean birth but have subsequently withdrawn this guideline.15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.