Trends in Incidence of Diabetes in Pregnancy and Serious Perinatal Outcomes

A Large, Population-Based Study in Ontario, Canada, 1996-2010

Denice S. Feig; Jeremiah Hwee; Baiju R. Shah; Giliian L. Booth; Arlene S. Bierman; Lorraine L. Lipscombe


Diabetes Care. 2014;37(6):1590-1596. 

In This Article

Abstract and Introduction


Objective. Women with diabetes in pregnancy have high rates of pregnancy complications. Our aims were to explore trends in the incidence of diabetes in pregnancy and examine whether the risk of serious perinatal outcomes has changed.

Research Design and Methods. We performed a population-based cohort study of 1,109,605 women who delivered in Ontario, Canada, between 1 April 1996 and 31 March 2010. We categorized women as gestational diabetes (GDM) (n = 45,384), pregestational diabetes (pre-GDM) (n = 13,278), or no diabetes (n = 1,050,943). The annual age-adjusted rates of diabetes in pregnancy were calculated, and rates of serious perinatal outcomes were compared between groups and by year using Poisson regression.

Results. The age-adjusted rate of both GDM (2.7–5.6%, P < 0.001) and pre-GDM (0.7–1.5%, P < 0.001) doubled from 1996 to 2010. The rate of congenital anomalies declined by 23%, whereas the rate of perinatal mortality did not change significantly. However, compared with women with no diabetes, women with pre-GDM and GDM faced an increased risk of congenital anomalies (relative risk 1.86 [95% CI 1.49–2.33] and 1.26 [1.09–1.45], respectively), and perinatal mortality remained elevated in women with pre-GDM (2.33 [1.59–3.43]).

Conclusions. The incidence of both GDM and pre-GDM in pregnancy has doubled over the last 14 years, and the overall burden of diabetes in pregnancy on society is growing. Although congenital anomaly rates have declined in women with diabetes, perinatal mortality rates remain unchanged, and the risk of both remains significantly elevated compared with nondiabetic women. Increased efforts are needed to reduce these adverse outcomes.


Diabetes in pregnancy is becoming an increasingly growing concern as the prevalence of diabetes continues to rise.[1] Women with diabetes who become pregnant have an increased risk of pregnancy complications,[2–7] including serious perinatal outcomes such as stillbirth, perinatal mortality, and major congenital malformations. Hyperglycemia in the period around conception and the first weeks postconception is a particular concern as it carries a substantially higher risk of congenital anomalies.[8] Studies have demonstrated reduced rates of congenital malformations and perinatal mortality with preconception counseling, where glycemic control is optimized, and comorbidities such as hypertension and diabetes complications are treated appropriately prior to and during pregnancy.[9,10]

Numerous advances over the last decade have the potential to reduce the rates of serious outcomes in women with diabetes. Such advances include the use of insulin analogs,[11] continuous glucose monitoring,[12] and the development of preconception clinics.[9] There is little data on whether the rates of these serious outcomes have changed over time in women with diabetes. Only two studies have looked at trends in outcomes in women with diabetes over the last decade, in Germany (data up to 2004) and the U.K. (data up to 2007), and both failed to find significant decreases in perinatal mortality or congenital anomalies.[13,14] Using unique population-based databases that link maternal and fetal health records, the aim of this population-based study was to compare rates of serious perinatal outcomes between women with and without diabetes in pregnancy, explore whether these rates have changed over time, and relate these rates to the underlying trends in rates of diabetes in pregnancy over the past 14 years. A secondary objective was to identify demographic and health care factors that predict serious outcomes in this population.