Prevalence and treatment of gestational diabetes in Norway 2010-2020

Aims: Estimate prevalence of gestational diabetes mellitus (GDM) and its treatment in Norway 2010-2020 and explore impact of new national GDM guidelines in 2017. Methods: We identified women giving birth in a nationwide cohort study using registers on births, prescriptions, education, primary and specialist care. For each year, we estimated prevalence of GDM overall, by BMI, age, education, and mother's birthplace; proportions of GDM pregnancies receiving pharmacological treatment; and distribution of the gestational week when GDM was diagnosed. Results: In 633,169 pregnancies, prevalence of GDM increased from 2.6 % in 2010 to 6.0 % in 2016, then stabilized. Similar patterns were seen across strata of BMI, age, education, and maternal birthplace, although prevalence was higher with higher BMI, higher age, lower education, and mothers born in Asia, Africa, or Middle East. The proportion of the GDM population pharmacologically treated increased from 11.6 % in 2010 to 13.6 % in 2016 and 31.6 % in 2020. GDM was diagnosed in recommended gestational week 24-28 in 19 % versus 45 % of GDM pregnancies in 2010 and 2020, respectively. Conclusions: Both the proportion diagnosed with GDM within recommended time of screening, and who received pharmacological treatment, increased substantially following new guidelines in 2017. Prevalence of GDM increased from 2010 to 2016, then plateaued.