A large and growing number of studies have focused on the increasing prevalence of gestational diabetes mellitus (GDM). We conducted a systematic review of the epidemiology of GDM and its prevalence with emphasis on the changes since the introduction of the International Association of Diabetes and Pregnancy Study Groups (IADPSG) 1 screening and diagnostic guidelines, endorsed by the World Health Organization2. This recommends a one-step 75g oral glucose tolerance test performed at 24-28 weeks, where GDM is diagnosed when any of the following plasma glucose cut-offs are met – fasting ≥5.1 mmol/L, 1-h ≥10.0 mmol/L, or 2-h ≥8.5 mmol/L.
Studies reporting the prevalence of GD were identified using PubMed, Scopus and Embase databases. Studies reporting on a countries’ GD prevalence or incidence data with a sample size greater than 1520 were deemed to be representative of that countries’ population and included in the review. Studies were also excluded if they were not published in English, or not original articles.
278 studies were identified that met the inclusion criteria since 1980, most being published in the North America, Europe and Asia-Pacific region. Prevalence rates varied greatly between regions – ranging from 3-19.5% in Africa; 2.3-19.9% in East/South-East Asia; 0.2-28.5% in Europe; 10 -24.2% in the Middle East; 1.8-19.2% in North America; 3.4-29.6% in Oceania; 13.4-35% in South Asia. There was heterogeneity within the regions in terms of ethnicities, screening and diagnostic practices which likely account for the variation.
Other factors accounting for the differences include increasing rates of obesity and maternal age. There has also been a marked rise after the year 2010 with the widespread adoption of the diagnostic criteria recommended by the IADPSG, with some prevalence rates reported as rising by over two-fold, particularly in East and South Asian and Middle Eastern countries.
The worldwide prevalence of GDM is steadily increasing, with a particularly sharp increase in prevalence occurring over the last decade since the adoption of IADPSG screening and diagnostic criterion.