The approaches used to screen and diagnose gestational diabetes mellitus (GDM) vary widely. We generated a comparable estimate of the global and regional prevalence of GDM by International Association of Diabetes in Pregnancy Study Group (IADPSG)'s criteria.Methods: We searched PubMed and other databases and retrieved 57 studies to estimate the prevalence of GDM. Prevalence rate ratios of different diagnostic criteria, screening strategies and age groups, were used to standardize the prevalence of GDM in individual studies included in the analysis. Fixed effects meta-analysis was conducted to estimate standardized pooled prevalence of GDM by IDF regions and World Bank country income groups. Results:The pooled global standardized prevalence of GDM was 14.0% (95% confidence interval: 13.97-14.04%). The regional standardized prevalence of GDM were 7.1% (7.0-7.2%) in North America and Caribbean (NAC), 7.8% (7.2-8.4%) in Europe (EUR), 10.4%

Ethnicity is defined as "belonging to a social group that has a common national or cultural tradition". Membership of certain ethnic groups has long been associated with increased risk of gestational diabetes mellitus (GDM). Studies that examined ethnic differences amongst women with GDM were often conducted in western countries where women from various ethnic backgrounds were represented. The prevalence of GDM appears to be particularly high among women from South Asia and South East Asia, compared to Caucasian, African-American and Hispanic communities. For some, but not all ethnic groups, the body mass index is a risk factor for the development of GDM. Even within a particular ethnic group, those who were born in their native countries have a different risk profile for GDM compared to those born in western countries. In terms of treatment, medical nutrition therapy (MNT) plays a key role in the management of GDM and the prescription of MNT should be culturally sensitive. Limited studies have shown that women who live in an English-speaking country but predominantly speak a language other than English, have lower rates of dietary understanding compared with their English speaking counterparts, and this may affect compliance to therapy. Insulin therapy also plays an important role and there appears to be variation as to the progression of women who progress to requiring insulin among different ethnicities. As for peri-natal outcomes, women from Pacific Islander countries have higher rates of macrosomia, while women from Chinese backgrounds had lower adverse pregnancy outcomes. From a maternal outcome point of view, pregnant women from Asia with GDM have a higher incidence of abnormal glucose tolerance test results post-partum and hence a higher risk of future development of type 2 diabetes mellitus. On the other hand, women from Hispanic or African-American backgrounds with GDM are more likely to develop hypertension post-partum. This review highlights the fact that management needs to be individualised and the clinician should be mindful of the impact that differences in ethnicity may have on the clinical characteristics and pregnancy outcomes in women affected by GDM, particularly those living in Western countries. Understanding these differences is critical in the delivery of optimal antenatal care for women from diverse ethnic backgrounds.

This study aims to examine the projected HIP prevalence in 2030 and 2045 using multiple methods. Methods: The International Diabetes Federation Diabetes Atlas 2019 prevalence was projected to 2030 and 2045 by: (1) carrying forward the 2019 age-adjusted prevalence rates; (2) applying a linear regression of the past four editions of the IDF Diabetes Atlas; (3) applying a regression of the previous editions with the most consistent trend, followed by extrapolation from the 9th edition HIP estimate. Results: Respectively, for 2030 and 2045, Method 1 projected a declining HIP rate with prevalences of 14.0% and 13.3%, Method 2 projected an increasing HIP prevalence at 16.5% and 18.3%, Method 3 predicted stabilisation of the rate from 16.0% to 15.8%. Conclusion: Assuming other factors remain unchanged, our best estimation of age-adjusted HIP will show stabilisation between 2019 and 2045 of 15.8% to 16.0%. However, this estimate is confounded by the heterogeneity of studies and the influence of different gestational diabetes mellitus diagnostic criteria. To provide accurate future comparisons we recommend standardising the diagnostic criteria to the International Association of Diabetes in Pregnancy Study Groups.