| Objective:Gestational diabetes mellitus(Gestational Diabetes Mellitus,GDM)is a series of clinical syndrome characterized by hyperglycemia after pregnancy,which has a great impact on mother and fetus.Obesity,as a chronic metabolic disease,has been proved to be closely related to the occurrence of GDM.Studies have found that there is a certain correlation between intestinal flora and overweight and GDM,and pregnant women overweight or GDM may affect the early development of offspring by affecting the establishment of neonatal intestinal flora.The purpose of this study was to sequence the intestinal microflora in the fresh feces of GDM and overweight pregnant women by 16 s rRNA high-throughput sequencing technique,and to analyze the dynamic changes of intestinal microflora from the second trimester to the third trimester of pregnancy,to explore the correlation between intestinal microflora and GDM and overweight,and to further clarify the possible mechanism of GDM and overweight,so as to provide new ideas for the diagnosis and treatment of overweight and GDM.Methods:In this study,pregnant women aged between 25 and 35 who were examined and hospitalized in Shanxi Maternal and Child Health Hospital from January to December 2019 were evaluated for body mass index(BMI)before pregnancy and 75 g glucose tolerance test was performed at 24 weeks of pregnancy.A total of 75 pregnant women were enrolled in the study,including 20 normal pregnant women(NG_NO group),20 simple GDM group(G_NO group)and 20 simple overweight group(NG_O group).GDM overweight group(15 cases).The first feces of pregnant women at 24 and 37 weeks of pregnancy were collected,and the 16 s rRNA V3-V4 variable regions of intestinal microbiota were sequenced by Illumina MiSeq PE300 sequencing platform,and bioinformatics analysis was carried out.Results:1.There was no significant difference in gestational age and gestational age among the four groups(P > 0.05).The weight gain of),GDM group was lower than that of non-GDM group,and the difference was statistically significant(P < 0.05).2.The relative distribution of intestinal flora at the gate level of pregnant women in each group:(1)comparison between groups: in the second trimester of pregnancy,there was no significant difference in the relative distribution of intestinal flora among normal pregnant women,simple GDM group,simple overweight group and GDM overweight group,mainly firmicutes(about 70%),followed by actinomycetes(about 13%),actinomycetes(about 10%)and Proteus(about 5%).In the third trimester of pregnancy,compared with the normal pregnant group,the proportion of firmicutes decreased and the proportion of Bacteroides increased in simple GDM group;the proportion of firmicutes decreased and the proportion of actinomycetes increased in simple overweight pregnant women;there was no significant change in GDM overweight pregnant women.(2)intra-group comparison: from the second trimester to the third trimester of pregnancy,the proportion of firmicutes decreased slightly and the proportion of Bacteroides increased slightly in normal pregnant women;in simple GDM group,the proportion of firmicutes decreased and that of Bacteroides increased;the proportion of simple overrecombination firmicutes and actinomycetes decreased,but the proportion of actinomycetes and Proteus increased slightly;the proportion of GDM super-recombinant firmicutes increased slightly,and the proportion of Proteus decreased slightly.3.OTU analysis of intestinal flora:(1)OTU difference analysis: in the second trimester,there were characteristic microorganisms in the classified water under the door of pregnant women in each group.The characteristic intestinal microorganisms in normal pregnant women were g_Ruminococcus,while those in simple GDM group were Desulfovibrionales,Desulfovibrionaceae,Deltaproteobacteria and Anaerostipes,and the characteristic intestinal microorganisms in normal pregnant women were Rumen cocci,Desulfovibrionaceae,Deltaproteobacteria and Anaerostipes.The characteristic intestinal microorganisms of simple overrecombination were Verrucomicrobia,Verrucomicrobiae,Verrucomicrobiales,Verrucomicrobiaceae and AKKermansia,while the characteristic intestinal microorganisms of GDM were Lactobacillus.In the third trimester of pregnancy,there were no characteristic intestinal microorganisms in normal pregnant women and simple GDM groups,the characteristic intestinal microorganisms in simple overweight pregnant women were Enterobacteriaceae and Enterobacteriales,and the characteristic intestinal microorganisms in GDM overrecombinant pregnant women were Gram Eubacterium,Pyramidobacter and Dethiosulfovibrionaceae.(2)OTU species analysis: the total number of OTU in the intestinal flora of normal pregnant women,simple GDM group,simple overweight group and GDM overweight group in the second trimester was 587,143,149,99,respectively,and the number of OTU in the third trimester was 156,545,120,183,91 in the third trimester,respectively.It can be seen that there are some differences in the OTU composition of the four groups of intestinal flora.The number of OTU in normal pregnant women was significantly higher than that in the other three groups.4.? diversity analysis:(1)comparison between groups: in the second trimester of pregnancy,the ? diversity index(chao1 index,Shannon index and Faith_pd index)of pregnant women with simple GDM and GDM overweight was slightly lower than that of normal pregnant women(P > 0.05),and the ? diversity of simple overweight pregnant women was lower than that of normal pregnant women(chao1 index,Faith_pd index and Shannon index).In the third trimester of pregnancy,the ? diversity index of simple overweight group was slightly lower than that of normal pregnant group,but there was no significant difference in ? diversity index between simple GDM group,GDM overweight group and normal pregnant group(P > 0.05).(2)intra-group comparison: there was no significant difference in ? diversity index among the four groups from the second trimester to the third trimester(P > 0.05).5.? diversity analysis:(1)comparison between groups: in the second trimester of pregnancy,there was no significant difference in the ? diversity index of intestinal flora between the simple GDM group and the normal pregnant group,but the ? diversity index of simple overweight and GDM overweight group was significantly higher than that of the normal pregnant group(P < 0.05).In the third trimester of pregnancy,there was no significant difference in the ? diversity distance of intestinal flora among simple GDM group,GDM overweight group and normal pregnant group,but the ? diversity distance of simple overweight group was significantly higher than that in normal pregnant group(P < 0.05).(2)intra-group comparison: there was no significant difference in the distance of ? diversity of intestinal flora among the four groups from the second trimester to the third trimester of pregnancy(P > 0.05).Conclusion:1.With the progress of pregnancy,compared with normal pregnant women,the proportion of firmicutes of pregnant women with GDM was significantly reduced,and the specific gravity of Bacteroidetes was significantly increased;the proportion of firmicutes of overweight pregnant women was significantly reduced,and the proportion of actinomycetes was significantly increased.2.? diversity of intestinal flora in overweight and GDM pregnant women is lower than that in normal pregnant women,especially in overweight pregnant women.3.GDM pregnant women through active weight control during pregnancy may have a positive effect on improving the ? diversity of intestinal flora.4.The ? diversity of intestinal flora was significantly different between overweight pregnant women and normal pregnant women. |
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