Gestational Diabetes Changes Gut Microbiota Composition During and After Pregnancy

by | Mar 9, 2020 | 2018, Diabetes, Pregnancy and Lactation, Women's Health

Written by Angeline A. De Leon, Staff Writer. Study finds that gut microbiota composition of pregnant women at time of gestational diabetes mellitus (GDM) diagnosis exhibited higher levels of  bacterial species associated with type 2 diabetes and metabolic syndrome.

pregnancy - women's healthPregnancy is accompanied with a number of physiological and metabolic changes, but in a subset of women who are predisposed, the development of gestational diabetes mellitus (GDM) can occur 1. In GDM, blood sugar levels become abnormally high and though they usually normalize after delivery, almost 50% of women with GDM incur an elevated risk of developing type 2 diabetes later in life 2. Emerging research suggests a strong relationship between imbalances in gut microbiota and metabolic changes such as increased insulin resistance 3-5. Studies in healthy pregnant women indicate significant changes in gut microbiota from the first to third trimester, where microbiota composition in the last gestational period was seen to resemble that of individuals with metabolic syndrome 6,7. Currently, there is a need to better understand the changes in maternal microbial composition from the time of late pregnancy to the time of early postpartum 8. In a study 9  conducted at the University of Copenhagen (2018), researchers compared the gut microbiota of pregnant women with GDM with that of healthy pregnant women with normal glycemic levels from the time of late pregnancy to about 8 months postpartum.

A total of 50 women with GDM (mean age = 34.4 years) and 157 healthy pregnant women (mean age = 33.3 years) completed two laboratory visits, once during their third trimester of pregnancy and again after an average of 8.8 months postpartum. At both visits, fasting blood samples were collected and analyzed for hormonal and metabolic biomarkers, and a standard 2-hour oral glucose tolerance test (OGTT) was completed to determine insulin and glucose homeostasis. Fecal samples were also collected within 48 hours of the OGTT and analyzed using a DNA sequencing technique to determine gut microbiota composition (taxonomic abundance of bacterial species represented in operational taxonomic units, OTUs).

Results indicated that there were significant differences in the gut microbiota composition of GDM women, compared with healthy normoglycemic women, at the phylum level (higher abundance of Actinobacteria in GDM) as well as genus level (higher abundance of Collinsella, Rothia, and Desulfovibrio in GDM). After adjusting for pre-pregnancy body mass index, tests identified 5 species-level OTUs (primarily within Firmicutes phylum) which were differentially abundant in GDM women vs. normoglycemic women during the third trimester of pregnancy (enrichment of OTUs assigned to Faecalibacterium and Anaerotruncus and depletion of OTUs assigned to Clostridium and Veillonella). Across all participants, OTU richness was seen to decrease from late pregnancy to postpartum follow-up (p = 0.0002). At 8-month postpartum follow-up, 13 OTUs were identified as being differentially abundant in women with preceding GDM, compared to women with preceding normoglycemic pregnancy.

Evidence from the present study confirms that GDM imposes changes in gut microbiota during late pregnancy that remain detectable even after several months postpartum. Relative to pregnant women with normal glycemic levels, GDM women exhibited higher levels of bacterial species that are associated with type 2 diabetes (Collinsella) 10 and metabolic syndrome (Faecalibacterium) 11, corroborating the potential link between GDM and later risk of metabolic disorder in select women. Richness of gut microbiota composition was also seen to significantly change from late pregnancy to postpartum. Overall results suggest that GDM is associated with aberrant changes in gut microbiota both during and after pregnancy. Researchers note that a primary limitation of the present study relates to the absence of fecal samples prior to pregnancy. Prospective trials are needed to establish a direct causal relationship between GDM and increased risk of diabetes and to more comprehensively evaluate the intestinal microbiome of GDM patients.

Source: Crusell MKW, Hansen TH, Nielson T, et al. Gestational diabetes is associated with change in the gut microbiota composition in third trimester of pregnancy and postpartum. Microbiome. 2018; 6: 89. DOI: 10.1186/s40168-018-0472-x.

© The Author(s). 2018 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/) (http://creativecommons.org/publicdomain/zero/1.0/)

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Posted March 9, 2020.

Angeline A. De Leon, MA, graduated from the University of Illinois at Urbana-Champaign in 2010, completing a bachelor’s degree in psychology, with a concentration in neuroscience. She received her master’s degree from The Ohio State University in 2013, where she studied clinical neuroscience within an integrative health program. Her specialized area of research involves the complementary use of neuroimaging and neuropsychology-based methodologies to examine how lifestyle factors, such as physical activity and meditation, can influence brain plasticity and enhance overall connectivity.

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