Pregnancy outcomes in gestational diabetes mellitus before and after applying International Association of Diabetes and Pregnancy study groups criteria in Guangzhou China

Background: Gestational diabetes mellitus (GDM) is carbohydrate intolerance resulting in hyperglycemia of variable severity with onset or first recognition during pregnancy. Although GDM is asymptomatic in most patients, it will lead to adverse perinatal outcomes such as macrosomia and postpartum hemorrhage, birth injury and increased cesarean section rate. Identifying populations at high risk of GDM will allow for proper interventions and may thus improve the adverse perinatal outcomes. In 2010, the International Association of Diabetes and Pregnancy Study Groups (IADPSG) developed new diagnostic criteria for GDM. Mild hyperglycemia according to the previous criteria such as the WHO criteria and NDDG criteria is now categorized as GDM by the IADPSG Criteria. However, there are more and more controversies on the effectiveness of the IADPSG Criteria since it was implemented. China has relatively high prevalence of GDM, and the prevalence will be much higher by using the IADPSG Criteria. Given the uncertainty of the effectiveness of the IADPSG Criteria, it is important to examine the potential harms or benefits of the IADPSG Criteria in China by examining the adverse perinatal outcomes. Objectives:(1) To assess the difference in pregnancy outcomes in a cohort of Chinese women before and another cohort after implementing the IADPSG Criteria.(2) To examine whether the intervention to the mild hyperglycemia group improved pregnancy outcomes. Setting: Guangzhou Women and Children’s Medical Center (GZWCMC). Methods: A historical cohort study was conducted to investigate the difference of adverse pregnancy outcomes of the GDM patients after the IADPSG Criteria was adopted in the GZWCMC. 114 pregnant women with overt diabetes and 244 pregnant women with mild hyperglycemia in 2010 were sampled from the cohort of 2010 when the IADPSG Criteria had not been applied. 121 pregnant women with overt diabetes and 195 pregnant women with mild hyperglycemia were sampled from the cohort of 2012 when the IADPSG Criteria had been applied. Data was collected from the medical records in the medical center. Comparison of adverse pregnancy outcomes between the overt diabetes patients in 2010 and in 2012 was performed to examine the variation of GDM outcomes over time. Comparison of adverse pregnancy outcomes between the mild hyperglycemic subjects in 2010 and 2012 was performed to examine the effectiveness of the interventions to the mild hyperglycemic subjects, because mild hyperglycemic subjects in 2010 did not receive interventions. Primary outcomes were large for gestational infant (LGA) and primary cesarean section. Binary logistic regression model was used to examine the differences of adverse outcomes with adjustment for potential confounders. Odds ratios (ORs) and P-values were used to demonstrate the relative risk and the significance of the results. Results: Baseline characteristics varied between the cohort of 2010 and cohort of 2012. Subjects in the 2012 cohort had lower body mass index (BMI), lower blood glucose and were diagnosed earlier. No differences of primary outcomes between the overt diabetes patients in 2010 and in 2012 were found after adjustment for maternal age, BMI, parity and gestational age at oral glucose tolerance test (OGTT). The OR for LGA and primary cesarean was 0.58 (95% confidence interval (CI):0.10-3.35, P=0.54) and 0.68 (95% CI: 0.33-1.39,P=0.29), respectively, suggesting that LGA and primary cesarean in overt diabetes patients did not vary over time. No differences of LGA and primary cesarean between the mild hyperglycemic subjects in 2010 and 2012 were observed after adjustment for maternal age, BMI, parity and gestational age at OGTT. The OR for LGA and primary cesarean section was 1.25 (95% CI: 0.46-3.40, P=0.66) and 0.78 (95% CI: 0.47-1.29, P=0.33), respectively. Compared with those with mild hyperglycemia in 2010, a lower risk for postpartum hemorrhage in those with mild hyperglycemia in 2012 was found (OR=0.05, 95% CI: 0.01-0.41). Conclusions: Our study has provided some evidence that the risks for most of the adverse pregnancy outcomes except postpartum hemorrhage, including LGA, primary cesarean, gestational hypertension, preterm birth, macrosomia and mean birth weight in pregnant women with mild hyperglycemia did not have significant differences before and after the IADPSG Criteria was adopted. Given the small sample size of the current study, we have yet to draw a definite conclusion that intervention to pregnant women with mild hyperglycemia improved adverse pregnancy outcomes from the results. Further large studies are needed to examine both the benefits and harms of implementing the IADPSG Criteria.published_or_final_versionPublic HealthMasterMaster of Public Healt