Temporal Trends in Type 1, Type 2, and Gestational Diabetes in Pregnancy: Impact of Rural Residence, Ethnicity, and Material Deprivation

Objective

Our aim in this study was to implement a newly validated algorithm to identify pregnant women with type 1 diabetes mellitus (T1DM), type 2 diabetes mellitus (T2DM), and gestational diabetes mellitus (GDM), and to identify temporal trends in rates over the last decade. We also compared obstetric and neonatal outcomes of pregnancies with and without diabetes mellitus (DM).

Methods

Among women with live births between 2005 and 2018 in Alberta, we calculated yearly rates of T1DM, T2DM, and GDM, overall, and stratified by ethnicity, urban or rural residence, material deprivation score, and maternal age.

Results

Between 2005 and 2018, GDM rates increased from 42.3 to 101.8 per 1,000 deliveries (p<0.0001), T2DM rates increased from 2.6 to 6.4 per 1,000 deliveries (p<0.0001), whereas T1DM remained constant at 3.0 per 1,000 deliveries each year (p=0.4301). Higher GDM and T2DM rates were observed among Chinese and South Asian women, respectively, and among women who were materially deprived and living in urban areas. Women with T2DM were older and had the highest rates of pre-existing hypertension (16%). In contrast, women with T1DM were younger and had the highest rates of gestational hypertension (12%), pre-eclampsia (12%), and cesarean section deliveries (62%). Children of women with T1DM had the highest rates of large for gestational age (46%), neonatal hypoglycemia (41.1%), respiratory distress syndrome (7.7%), and jaundice (29.3%).

Conclusions

Diabetes-in-pregnancy rates have more than doubled over the last decade, driven primarily by increases in GDM and T2DM. These trends may have significant implications for the future health of mothers and children in Alberta.