The prevalence and predictors of gestational diabetes mellitus in Hungary.

There are conflicting results regarding the frequency of gestational diabetes (GDM) in Hungary. The aim of this study was to estimate the prevalence of GDM and to clarify the association between selected maternal characteristics and GDM risk. In a population-based screening program of GDM in Tolna County, Hungary, 75 g OGTTs were offered to all pregnant women between 24-28 weeks of gestation and evaluated according to WHO criteria in 2000 (WHO GDM). Women were also classified based on the IADPSG criteria (IADPSG GDM). Selected risk factors were recorded by district nurses. OGTT results were available for 1,835 (81.2%) pregnancies out of 2,261. Altogether 159 (8.7%) were diagnosed as WHO GDM and 304 (16.6%) as IADPSG GDM. Gestational diabetes was related to older age, higher BMI, and an increasing number of deliveries (all p<0.005). The risk of IADPSG GDM monotonously increased with age, -pre-pregnancy BMI and number of deliveries. The risk of WHO GDM increased linearly with age, however, women with the highest BMI (≥ 29.2 kg/m2) had decreased risk compared to women with a BMI of 26.1-29.1 kg/m2 (p<0.05). There was an inverse U-shaped association between GDM risk and number of deliveries with the highest risk observed in those with 3 deliveries (p quadratic term=0.008). We found a high prevalence of GDM in this Caucasian Hungarian population. Our results suggest that pre-pregnancy BMI and previous deliveries elevate the risk of WHO GDM only to a certain level, above which the risk decreases.