Effects of Nutritional Therapy on Blood Glucose Levels and Pregnancy Outcomes in Patients with Gestational Diabetes Mellitus: A Meta-Analysis

Objective This meta-analysis aims to further evaluate the effect of nutrition therapy on the GDM patients during pregnancy, to provide a more reliable theoretical basis for the clinical promotion and application of nutrition therapy, so as to improve maternal and child health. Methods The literatures on nutrition therapy for GDM were obtained by searching PubMed, Cochrane Library, CBM, EBSCO, EMBASE and Web of Science, and the time range of the search was from the time of establishment of database to July 2020. Then the obtained literatures were screened based to the inclusion and exclusion criteria to extract the relevant data and evaluate the risk of bias from the included RCTs. Finally, the RevMan 5.3 statistical software provided by the Cochrane Collaboration was used for the meta-analysis of the extracted data. Results In this meta-analysis, 12 RCTs, a total of 837 patients with GDM, were included. The analysis results showed that there were not statistically significant differences between the nutrition therapy group and the control group in FPG (SMD =-0.50, 95% CI: -1.15~0.15, P=0.13), 2hPG (SMD=-0.01, 95% CI: -0.44~0.41, P=0.95), HbAlc (SMD=0.38, 95%CI: -0.90~1.65, P=0.56), cesarean section (RR=0.78, 95% CI: 0.60~1.01, P=0.06), polyhydramnios (RR=0.32, 95% CI: 0. 04~2.99, P=0.32) and neonatal hypoglycemia (RR=0.68, 95% CI: 0.35~1.30, P=0.24), but were statistically significant differences in maternal weight gain during pregnancy (SMD =-0.26, 95% CI: 0.48~0.04, P=0.02) and macrosomia (RR=0.19, 95% CI: 0.08~0.48, P=0.0005). Conclusion This meta-analysis indicates that nutrition therapy that change the amount of carbohydrates, fats, energy and low-GI or low-GL foods in daily diet can decrease the maternal weight gain during pregnancy and lower the incidence of macrosomia, and may reduce the occurrence of cesarean section in the patients with GDM; but it do not effectively improve other outcomes. Nevertheless, given the difference between this analysis and other systematic reviews, so the studies with more high quality in the future should be implemented to further explore more effective approach of nutritional therapy for GDM and determine the reliability of the results.