Pregnancy Outcomes and Insulin Requirements in Women with Type 1 Diabetes Treated with Continuous Subcutaneous Insulin Infusion and Multiple Daily Injections: Cohort Study

Background: We aimed to compare glycemic control, insulin requirements, and outcomes in women with type 1 diabetes in pregnancy treated with continuous subcutaneous insulin infusion (CSII) and multiple daily injections (MDI). Methods: A retrospective cohort study was conducted of singleton pregnancies (>20 weeks gestation) in women with type 1 diabetes (2010-2015) at a specialist multidisciplinary maternity network in Australia. Antenatal characteristics, diabetes history and treatment details, and maternal and neonatal outcomes were compared for women with type 1 diabetes using CSII and MDI. Bolus calculator settings were reviewed for CSII. Data were obtained from individual medical records, linkage to pathology, and the Birthing Outcomes System database. Results: There were no differences in maternal characteristics or diabetes history between women managed with CSII (n = 40) and MDI (n = 127). Women treated with CSII required less insulin and less increase in total daily insulin dose/kg than MDI (40% vs. 52%). Both groups achieved similar glycemic control and no differences in pregnancy outcome. In the CSII group, carbohydrate:insulin ratios were intensified across gestation (30% breakfast, 27% lunch, 22% dinner), and insulin sensitivity factors (ISFs) changed little (7% breakfast, 0% lunch, -10% dinner). Conclusions: There was no difference in glycemic control or pregnancy outcomes in women using CSII or MDI managed in a multidisciplinary setting. Greater adjustments are needed to ISFs with CSII therapy. Overall, these data do not support recommending CSII in pregnancy with potentially higher patient and staff demands and costs and lack of improvement in HbA1c and pregnancy outcomes.