Does the Change in the Diagnostic Criteria for Gestational Diabetes in Poland Affect Maternal and Fetal Complications? A Prospective Study.

Background and objectives: Gestational diabetes mellitus (GDM) is a significant risk factor of maternal and fetal complications. The aim of the study was to compare two groups of patients with GDM treated in 2015/2016 (Group-15/16), and in 2017/2018 (Group-17/18) and to answer the question whether the change in the diagnostic criteria for GDM affected maternal and fetal complications. Materials and Methods : A retrospective analysis was conducted. The study included 123 patients with GDM (58 patients/Group-15/16 and 65 patients/Group-17/18). Results: No significant differences were found between the groups. In Group-17/18, GDM was significantly more often diagnosed based on fasting glycemia (33.8%) compared with Group-15/16 (22.4%; p = 0.000001). GDM was significantly more often diagnosed based on 2-h oral glucose tolerance test (OGTT; 44.8%) compared with Group-17/18 (29.2%; p = 0.000005). In Group-15/16, insulin was started in 51.7% of patients compared with 33.8% in Group-17/18 ( p = 0.04287). Despite more frequent insulin therapy in Group-15/16, insulin was started later (30th week of gestation) and significantly more frequently in older patients and those with higher BMI values compared with Group-17/18 (27th week of pregnancy). The number of caesarean sections and spontaneous deliveries was also similar in both periods. No difference was found in the prevalence of neonatal complications, including neonatal hypo-glycemia, prolonged jaundice or heart defect. In addition, no differences were found between the parameters in newborns. Conclusions: The change in the criteria for the diagnosis and treatment of GDM translated into the mode of diagnosis and currently it is more often diagnosed based on abnormal fasting glycemia. Currently, a lower percentage of patients require insulin therapy. However, less frequent inclusion of insulin may result in higher postprandial glycemia in the third trimester of pregnancy in mothers, thus increasing the risk of neonatal hypoglycemia immediately after delivery.