Background: The importance of glycaemic control in pregnancy is well-established. The Pregnancy-IVI Is a validated, midwife-led, intravenous-insulin (IVI) algorithm, demonstrated to control maternal intrapartum glucose, and may reduce neonatal hypoglycaemia after betamethasone (1,2). Materno-fetal outcomes are presented from a large cohort of women with diabetes, managed with Pregnancy-IVI in a tertiary centre.
Methods: All women receiving Pregnancy-IVI following betamethasone (2017-2022) had data systematically extracted from eMR using a standardised template. Outcomes for mothers receiving two doses of 11.4mg betamethasone 24 hours apart, and infants born within 48-hours of betamethasone, were sub-analysed. Univariate analysis of factors associated with outcomes was performed.
Results: In the whole maternal cohort (n=435, GDM=79% T1DM=13%, T2DM=8%), mean age was 32.1±5.8 years and gestational age at betamethasone 33.5±3.4 weeks. 63% of women were treated with subcutaneous insulin pre-admission (GDM=54%, T1DM=100%, T2DM=89%). On-infusion maternal glucose time-in-range (TIR, 4.0-7.8mmol/l) was 83%[IQR 77–90%] and mean on-IVI glucose 6.6±0.6mmol/L. Maternal hypoglycaemia (<3.8mmol/L) was uncommon (0.54 hours/100 on-IVI woman-hours).
In mothers receiving two betamethasone doses (n=347), factors associated with lower maternal glucose time-in-range included diabetes type (TIR GDM=85%, vs. T1DM=78% vs. T2DM=75%, p=0.01) and presence of intra-uterine infection (TIR 77%(n=47) vs. 83%(n=300), p<0.001). Maternal age, gestational age and BMI were not significant factors. Median on-IVI infused insulin dose was 59iu/24hours[IQR 40-86]. Higher infused insulin dose was associated with diabetes type (GDM=59[IQR 38-79 vs. T1DM=51[IQR 40-74] vs. T2DM=83[IQR 54-114]iu/24hours, p<0.001), increasing BMI (beta-coefficient=0.89, p<0.001) and earlier gestational age (beta-coefficient=–1.23, p=0.04). For women continuing pre-admission prescribed subcutaneous insulin during Pregnancy-IVI(n=123), the ratio of IVI to baseline subcutaneous insulin dose was 2.3[IQR1–4.3] for GDM, 0.7[IQR0.4-1] for T1DM, and 0.8[IQR0.5-1.8] for T2DM (p<0.001 GDM vs. T1DM/T2DM).
Neonates born within 48h of betamethasone(n=218) developed neonatal hypoglycaemia(<2.5mmol/L) at a rate of 33% for mothers with GDM, 64% for T1DM and 59% for T2DM. Of the sub-population of neonates with mothers receiving two doses of betamethasone (n=136), neonatal hypoglycaemia was more common in pre-existing diabetes (p<0.001). Neonatal hypoglycaemia was also associated with higher maternal glycaemic variability (coefficient of variation) (p=0.03), and lower with increasing glucose time-in-range 4.0-7.8mmol/l (p=0.02), but these measures were confounded by diabetes type.
Conclusion: The Pregnancy-IVI controls maternal glucose after betamethasone. After two doses of betamethasone, women with GDM require higher percentage increases in insulin compared to women with T1DM/T2DM. Pre-existing diabetes remains significantly associated with neonatal hypoglycaemia following betamethasone despite intensive peripartum glycaemic control .