Pregnancy Outcomes and Maternal Characteristics in Women with Pregestational and Gestational Diabetes: A Population-Based Study in Spain, 2016–2022

<b>Background/Objectives</b>: The objective of this study was to compare trends in the incidence of deliveries and in obstetric interventions and outcomes in women with and without type 1 diabetes (T1DM), type 2 diabetes (T2DM), and gestational diabetes (GDM). <b>Methods</b>: This was an observational study using the Spanish National Hospital Discharge Database (2016-2022). <b>Results</b>: A total of 1,995,953 deliveries were recorded between 2016 and 2022 (6495 mothers with T1DM, 5449 with T2DM, and 124,172 with GDM). The incidence of T1DM and GDM increased over time, although it remained stable in women with T2DM. Women with T2DM were more likely to have obstetric comorbid conditions (72.93%) than women with GDM (63.04%), women with T1DM (59.62%), and women who did not have diabetes (45.3%). Pre-eclampsia, previous cesarean delivery, and arterial hypertension were the most prevalent conditions in all types of diabetes. The highest frequency of cesarean delivery was recorded for women with T1DM (55.04%), followed by women with T2DM (44.94%), and those with GDM (28.13%). The probability of cesarean delivery was 2.38, 1.79, and 1.19 times greater for T1DM, T2DM, and GDM, respectively, than for women who did not have diabetes. The adjusted rate for severe maternal morbidity was significantly higher for women with T1DM (RR 2.31; 95%CI 2.02-2.63) and T2DM (RR 1.58; 95%CI 1.34-1.87) than for women without diabetes. <b>Conclusions</b>: The incidence of deliveries in women with T2DM remained unchanged between 2016 and 2022; the incidence of deliveries increased in women with T1DM and GDM. The prevalence of comorbidity and obstetric factors increased over time in women with T1DM and GDM.