Biography
Biography: Engin Korkmazer
Abstract
The optimal time to screen and which test to use for GDM remains unclear. Currently, American College of Obstetricians and Gynecologists (ACOG), National Institute for Health and Clinical Excellence (NICE) recommend routine risk-factor-based screening (eg, previous gestational diabetes or known impaired glucose metabolism, obesity ) but International Association of Diabetes and Pregnancy Study Groups (IADPSG), United States Preventive services Task Force (USPSTF), American Diabetes Association (ADA), Canadian Diabetes Association (CDA) recommended universal screening in asymptomatic pregnant women at 24-28 weeks (3-4-5-6). Recent studies showed selective-screening missed one third of GDM patients and since 90% of pregnant women have at least one risk factor during pregnancy, universal screening seems to be logical (7-8). Screening methods for GDM are fasting glucose, random glucose, glycated hemoglobin (A1C) or more commonly, 50 gram (g) glucose challenge test (GCT). In GCT, after taking oral 50 g glucose, without considering time of last meal, plasma glucose level is measured one hour later. At the threshold 140 mg /dL, 80-90% of patients will be detected. For diagnosis of GDM, one step or two step approach is used. In one step approach diagnostic test (oral glucose tolerance test (OGTT) is performed without previous screening and in two step approach after GCT, diagnostic test (OGTT) is performed in high risk population. Controversies exist on amount of glucose load (75 g or 100 g), number of high cut–off values and duration of test. With recent study, the Hyperglycemia and Adverse Pregnancy Outcome (HAPO), it was the first study demonstrated an association between hyperglycemia and neonatal outcome, after performing 2 hour 75 g OGTT (9). After HAPO study, the IADPSG developed recommendations for the diagnosis and classification of hyperglycemia in pregnancy (10). The recommendations of IADPSG for GDM were screening high-risk population early in pregnancy and universal screening with 75 g 2 hour OGTT from 24-28 weeks of gestation and accepting one abnormal value enough for diagnosis of GDM (10). Even though, these recommendations are evidence based they did not achieved acceptance by all associations. ACOG advices to continue screening with two step strategy (GCT followed by a 100 g 3-hour OGTT) using the Carpenter & Coustan criteria only when the GCT is abnormal) at 24-28 weeks gestation (3). The National Institutes of Health (NIH) believed IADPSG criteria will increase costs and interventions and recommends two-step approach to be continued (11). In a recent systemic review considering 75 g 2-hour OGTT versus 100 g 3-hour OGTT; study showed that women having 75 g 2-hour OGTT had a higher relative risk of being diagnosed with GDM (risk ratio (RR) 2.55, 95% confidence interval (CI) 0.96 to 6.75). In the study, evidence was found insufficient to assess which strategy is best for diagnosis of GDM (12)."