Efficacy and safety of the pregnancy-IVI, an intravenous insulin protocol for pregnancy, following antenatal betamethasone in type 1 and type 2 diabetes

Aims: Hyperglycaemia following antenatal corticosteroids is common in womenwith diabetes in pregnancy, and validated algorithms to maintain pregnancy-specificglucose targets are lacking. The Pregnancy-IVI, an intravenous-insulin (IVI) algo-rithm, has been validated in gestational diabetes" however, its performance in pre-existing diabetes (Type 1 and Type 2 diabetes) is not known. We hypothesised that Pregnancy-IVI would be superior to a generic Adult-IVI protocol (prior standard of care) following betamethasone in women with pre-existing diabetes.

Methods: A retrospective cohort study enrolled all women with pre-existing diabetes at a tertiary centre receiving betamethasone and treated with IVI according to one of two protocols: Adult-IVI (n = 73, 2014–2017) or Pregnancy-IVI (n = 62,2017–2020). The primary outcome was on-IVI glycaemic time-in-range (capillary blood glucose (BGL) 3.8–7.0 mmol/L). Secondary outcomes included time with critical hyperglycaemia (BGL > 10 mmol/L)" occurrence of maternal hypoglycaemia (BGL < 3.8 mmol/l) and incidence of neonatal hypoglycaemia (BGL ≤ 2.5 mmol/L).Analysis was stratified by diabetes type.

Results: Overall, Pregnancy-IVI achieved a higher proportion of on-IVI time-in-range (70%, IQR 56–78%) compared to Adult-IVI (52%, IQR 41–69%, p < 0.0001).The duration of critical hyperglycaemia with Pregnancy-IVI was also reduced (2%[IQR 0–7] vs 8% [IQR 4–17], p < 0.0001), without an increase in hypoglycaemia. Glycaemic variability was significantly reduced with Pregnancy-IVI. No difference in the rate of neonatal hypoglycaemia was observed. The Pregnancy-IVI was most effective in women with Type 1 diabetes.

Conclusion: The Pregnancy-IVI algorithm is safe and effective when used following betamethasone in type 1 diabetes in pregnancy. Further study of women with type 2diabetes is required.