Endocrine Abstracts

Introduction: Insulin is standard of care for the treatment of type 1 diabetes (T1DM). Constant insulin adjustment is necessary to keep up with the different insulin requirements of pregnancy. Rapid, flexible and precise dosing of basal insulin and advanced options of bolus calculator settings for prandial insulin make insulin pump optimal solution.

Aim: The aim of the study was to explore pattern of insulin dynamic in pregnancies of T1DM patients with tight glycaemic control treated with insulin pump.

Material and methods: Data from 14 women with T1DM were retrospectively analyzed. Patients were treated with insulin pump, monthly followed by same endocrinologist and obstetrician at University Hospital Centre Zagreb, Department of Endocrinology and Diabetes and Croatian State Referral Centre for Diabetes in Pregnancy. Average time from pump initiation to conception was 19 months (2–78). At the time of conception median age was 28.5 years (25–34), median body mass index 23.1 kg/m² (19–33) and median weight gain during pregnancy 13 kg (4–16).

Results: All patient were successfully delivered by caesarean section without peripartal complications; median week of delivery was 38 (37–39), median APGAR score 10 (7–10), median birth weight 3190 g (2670–4440). At the time of conception median A1C was 6.5% (4.8–7.0). In the last trimester A1C was significantly lower with median 5.25% (4.6–7.1%), (P 0.020). Median total daily insulin dosage (TDD) at time of conception compared to 32nd week of pregnancy increased significantly (P 0.006) from 34.7 IU (13.4–50.6) to 43.85 IU (17.5–87.0). Contrary, total daily insulin dose per kilogram of body weight (TDD/kg) did not significantly change; at the time of conception it was 1.88 IU/kg (1.27–4.53) and at 32nd week of pregnancy 1.72 IU/kg (1.08–4.0). Basal/prandial insulin ratio at the time of conception was 52/48 changing significantly to 38/62 in the third trimester, (P 0.001).

Conclusion: In this study TDD increased for 21% throughout the pregnancy. Surprisingly, TDD/kg remained the same. Having in mind specific insulin demands in second and third trimester due to postprandial hyperglycemia, consecutive changes in insulin pump setting (bolus calculator) were made. The setting adjustments resulted in decrease of carbohydrate-to-insulin ratio followed by increase of prandial component of insulin and decrease of the basal one. This study points to the importance of redistribution of insulin components beyond weight-based dosing in pregnant patients with T1DM. Our findings suggest that such approach with steady TDD/kg of exogenous insulin during pregnancy enables tight glycaemic control without hyperinsulinisation.