Insulin requirements during pregnancy in women with type 1 diabetes treated with insulin pump

Introduction: Insulin requirement in women with Type 1 diabetes (T1DM) changes throughout pregnancy. The aim of this study was to determine the total change in insulin requirements and the effect of gestational weight gain (GWG) and pre-gestational BMI on insulin requirements during pregnancy in women with T1DM treated with continuous subcutaneous insulin infusion and continuous glucose monitoring. Methods: This historical cohort study included all consecutive women with T1DM who were monitored during pregnancy at the high-risk pregnancy clinic at a tertiary medical center during April 2011–April 2019. One Way Repeated Measures ANOVA with Bonferroni adjustment was conducted to compare the effects of gestational age on insulin requirements and a Two Way Repeated Measures ANOVA was employed to test for the interaction between gestational age intervals and maternal BMI and GWG. Results: Data regarding insulin requirements of 185 pregnancies were included in the analyses. There was a significant effect of gestational age on total insulin (Wilks' Lambda = 0.34, F(6,14) = 4.52, p = 0.009), basal insulin (Wilks' Lambda = 0.41, F(6,14) = 3.30, p = 0.031) and bolus insulin (Wilks' Lambda = 0.43, F(6,14) = 3.02, p = 0.041). Total insulin/kg requirements increased by 5.5% from 13–20 weeks to 20–26 weeks, 19% from 20–26 weeks to 26–33 weeks, and 17.4% from 26 to 33 weeks to delivery (p for trend = 0.009). Overall, insulin requirements increased by 42.1% from conception to delivery (p < 0.01). There was no significant main effect of maternal BMI or GWG on insulin requirements. Conclusions: There is a significant increase in insulin requirements per kg during pregnancy in women with T1DM who were treated with an insulin pump.