Carbohydrate metabolism and the species composition of the intestinal microbiota in women with gestational diabetes mellitus
Authors: Zinina Tatyana A. , Tiselko Alena V. , Yarmolinskaya Maria I. 
Published: July 2023

BACKGROUND: The prevalence of gestational diabetes mellitus has increased significantly and has become a global health problem, affecting 9.325.5% of pregnant women worldwide. Violation of the interaction of various body systems with the intestinal microbiota can be the cause of the development of insulin resistance. The study of the state of the intestinal microbiota based on the results of the study of the species composition of microorganisms in feces by the polymerase chain reaction method is necessary to understand the mechanisms of gestational diabetes mellitus development.
AIM: The aim of this study was to evaluate the intestinal microbiota status in women with normal pregnancy and pregnancy complicated by gestational diabetes mellitus.
MATERIALS AND METHODS: We examined 51 pregnant women in the period 2020-2022. The average age of women with normal pregnancy (n = 20) and pregnancy complicated by gestational diabetes mellitus (n = 31) was 29 (27.0; 32.5) and 31 (27.0; 35.0) years, respectively. The intestinal microbiota status was assessed based on the microbial species composition in feces using real-time polymerase chain reaction. All women underwent a test for carbohydrate metabolism at various gestation periods.
RESULTS: We have established a positive relation between Bacteroides thetaiotaomicron and Body Mass Index before pregnancy (r = 0.42). The number of Bacteroides thetaiotaomicron in the 1st, 2nd and 3rd trimesters of gestation positively correlated with the initial weight of women before pregnancy (r = 0.60, r = 0.52, r = 0.47, respectively; p 0.05). The Bacteroides spp. / Faecalibacterium prausnitzii ratio in women with gestational diabetes mellitus was negatively correlated with the average blood glucose level in the 3rd trimester of pregnancy (r = 0.81; p 0.05). Parvimonas micra positively correlated with venous plasma glucose levels in the presence of gestational diabetes mellitus (r = 0.58; p 0.05). A positive relationship was obtained between the number of Escherichia coli in pregnant women in the 1st trimester and the average glucose level in the 3rd trimester of pregnancy (r = 0.41; p 0.05). It was demonstrated that the growth of Bacteroides fragilis in the large intestine of pregnant women with gestational diabetes mellitus in the 3rd trimester of pregnancy correlated with subnormal blood glucose levels (r = 0.77; p 0.05), which may be due to a diet disorder (insufficient carbohydrate intake) or insulin overdose, which can lead to hypoglycemic conditions. In the group of women with gestational diabetes mellitus, a positive correlation was obtained between glycated hemoglobin level and the opportunistic pathogen Klebsiella pneumoniae representative amount in the 1st trimester of pregnancy (r = 0.46; p 0.05). In addition, we have found positive relations between the Citrobacter spp. / Enterobacter spp. ratio and the maximum blood glucose level in women with gestational diabetes mellitus in the 1st, 2nd and 3rd trimesters of pregnancy (r = 0.49, r = 0.43, r = 0.47, respectively; p 0.05). The difference in the intake of dietary fiber in the control group and in the group of pregnant women with gestational diabetes mellitus was obtained: 2 (1; 3) and 1 (1; 1), respectively (p 0.05).
CONCLUSIONS: Data have been obtained confirming the relationship between disorders of the colon microbiocenosis and carbohydrate metabolism in pregnant women with gestational diabetes mellitus. A relationship has been found between insufficient intake of dietary fiber and the risk of developing gestational diabetes mellitus.