Prevalence of gestational diabetes mellitus and results of the screening tests at a tertiary referral center: A cross-sectional study.

OBJECTIVE: This study aimed to identify the gestational diabetes mellitus (GDM) prevalence of low risk pregnant population at a tertiary referral center by different approaches.

MATERIAL AND METHODS: A cross-sectional study using retrospective data between 2007-2017 was conducted. During this period 77227 patients underwent either two step or one step glucose tolerance tests.

RESULTS: The median age of the study population was 27 (15-49). Fasting plasma glucose (FPG) testing was evaluated in 144,113 women at the initial antenatal care visit which %21 of these were between 92-126 mg/dL. Of these women %1.25 had FPG>126 mg/dL which showed the prevalence of pregestational diabetes in our cohort. During the study period 74412 women underwent 50-g glucose challenge test where %18 were screen positive and % 2.9 was defined as gestational diabetic without need for further testing (>180 mg/dL). The screening positive patients were sent to 100-g oral glucose tolerance test and the prevalence of GDM with two-step screening was 5.5%. A total of 2815 patients were screened by 75-g glucose tolerance test and the prevalence of GDM with one-step screening was 21%. Overall 4684 patients have been diagnosed as gestational diabetes mellitus with the prevalence of 6.07%.

CONCLUSION: Fasting plasma glucose >92 mg/dL is challenging in our population due to improper fasting. The FPG dependent GDM prevalence is almost four times higher than two-step glucose screening test results (21.8% vs 5.5%). If FPG levels will be used for diagnosing GDM then the values must be checked in a second laboratory analysis.