An Investigation into the Correlation of Intestinal Flora with Obesity and Gestational Diabetes Mellitus

METHOD: Thirty-two pregnant women aged 25-35 who were hospitalized in Shanxi Maternal and Child Health Hospital from January 2019 to December 2019 were included for evaluation, including 15 normal pregnant women (NG_NO group), 6 pregnant women with GDM alone (G_NO group), and 7 pregnant women with overweight alone (NG_O group). Stools were collected from pregnant women at 24 and 37 weeks of gestation and newborns' first meconium. The v3-v4 variable region of the gut flora 16s rRNA was double-ended sequenced and bioinformatically analyzed using the Illumina MiSeq PE300 sequencing platform. RESULTS: In the third trimester of pregnancy, there were significant differences in the composition of intestinal flora between the simple overweight group, simple GDM group, and normal pregnant group. From the second trimester to the third trimester, there was no significant change in the relative distribution of intestinal flora at the phyla classification level in normal pregnant women. The relative distribution of intestinal flora at the phylum level of newborns was significantly different from that of their mothers. The characteristic intestinal microbes of newborns in simple GDM group were g_Diaphorobacter, while the simple recombinant neonates were Nocardiaceae (f_Nocardioidaceae). In addition, the results showed significant differences in intestinal flora among the normal pregnant women group, simple GDM group, simple overweight group, and GDM overweight group. The results of β diversity analysis showed a significant difference in intestinal microflora species composition structure between the simple overweight group and the normal pregnant group in the second trimester of pregnancy. The species composition structure of intestinal flora was similar between the simple GDM group and the normal pregnant group. In the third trimester of pregnancy, there was no significant difference in the β diversity index among the groups, and the composition and structure of intestinal flora were similar. There were significant differences in the composition structure (β diversity) of intestinal flora between pregnant women and their newborns in each group (P < 0.05). Correlation analysis showed that the blood glucose values of oral glucose tolerance test (OGTT)_1 h and OGTT_2 h were positively correlated with Bacteroides (Bacteroides) and negatively correlated with Proteus (Prevotella), prepregnancy BMI was negatively correlated with Bacteroides, and weight gain during pregnancy was negatively correlated with Vibrio (Desulfovibrio) in Proteus. The birth weight of newborns was positively correlated with Actinomycetes (Actinomyces), Bacteroides (Faecalibacterium), and microbacilli (Dialister) and negatively correlated with Rolston (Ralstonia). CONCLUSION: Gut microbiota is strongly linked to obesity and gestational diabetes.