Insulin Pump Settings During Breastfeeding in Women with Type 1 Diabetes

Background: We aimed to explore insulin pump settings in breastfeeding women with type 1 diabetes. Methods: Thirteen unselected breastfeeding women with type 1 diabetes on insulin pump therapy were included consecutively from April 2016 to October 2017. Blinded continuous glucose monitoring (CGM) for 6 days was applied at 1, 2, and 6 months after delivery. Recommendations were intake of 210 g carbohydrate daily while aiming for glucose target range 4.0-10.0 mmol/L and avoiding hypoglycemia. Immediately after delivery a reduction of total insulin dose by 30% of the prepregnancy dose was recommended. Insulin pump target glucose was 5.8 mmol/L. Results: Median diabetes duration was 22 (range 13-36) years. At 1, 2, and 6 months, 13, 11, and 8 women, respectively, were breastfeeding and spent ≥70.8% (25%-99%) of time in the glucose target range and ≤3.8% (0%-15.5%) of time with CGM <4.0 mmol/L at night-time and for 24 h. None of the women experienced severe hypoglycemia. HbA1c was 58 (47-72) mmol/mol and 52 (44-60) at 6 months and prepregnancy, respectively, P  = 0.18. At 1, 2, and 6 months, the insulin pump settings remained almost stable with basal insulin rates (at 03.00, 08.00, 12.00, and 18.00) 14% lower and the carbohydrate-to-insulin ratios 10% higher than the prepregnancy settings. Conclusions: In breastfeeding women with type 1 diabetes who consumed sufficient amounts of carbohydrates and obtained appropriate glycemic control, the basal insulin rates were 14% lower and carbohydrate-to-insulin ratios 10% higher than before pregnancy. These data are useful when recommending insulin pump settings after delivery.