Glycemic control and selected pregnancy outcomes in type 1 diabetes women on continuous subcutaneous insulin infusion and multiple daily injections: the significance of pregnancy planning

Two regimens are used to achieve excellent glycemic control during pregnancy in type 1 diabetes mellitus (T1DM): continuous subcutaneous insulin infusion (CSII) and multiple daily injections (MDI). We assessed their efficacy and safety and the effect of pregnancy planning. We examined 269 pregnant T1DM women: 157 treated with MDI (MDI group), 42 with CSII (CSII group), and 70 who switched from MDI to CSII in the first trimester (MDI/CSII group). There were 116 women who planned pregnancy: 58 in the MDI group, 38 in the CSII group, and 20 in the MDI/CSII group. The estimated differences in glycemic control and maternal and fetal outcomes were adjusted for baseline characteristics. Mean glycated A1c (HbA1c) in the first trimester in the whole group was 6.9%, and the women differed depending on whether they planned pregnancy or not (P < 0.0001). A multiple regression model showed an average difference of about 0.9% in favor of pregnancy planning, with no interaction between the planning and treatments. In the second trimester, HbA1c decreased to a mean value of 5.8%, with improvement of HbA1c across all treatments: by 1.5% in not-planning and 0.9% in planning women. Despite greater improvement, not-planning women still had a higher HbA1c (by 0.3%, P = 0.05). In the third trimester, there was no further significant changes; nevertheless, women who planned pregnancy still had a lower HbA1c (by 0.5%, P = 0.02). There were 14 malformations, stillbirths, and perinatal infant deaths in the not-planning versus five in the planning group (P = 0.07). Patients in the CSII group had a 2 kg greater weight gain compared to the MDI group (15.0 kg vs. 13.0 kg; P = 0.005). In pregnancy with T1DM, both MDI and CSII can provide excellent glycemic control. Pregnancy planning has a beneficial effect on glycemic control, independent from the therapy model. CSII seems to predispose to a larger weight gain in mothers.