Poster Presentation Australasian Diabetes in Pregnancy Society and Society of Obstetric Medicine Australia and New Zealand Joint Scientific Meeting 2021

Changes in the gut microbiota of women with gestational diabetes mellitus: a microbiome understanding in maternity sub-study (#89)

Leanne Wang 1 2 , Emily McGovern 3 , Amanda Henry 1 2 , Georgina Hold 3 4 , Emad El-Omar 3 4 , Daniella Susic 1 2 3
  1. School of Women’s and Children’s Health, UNSW Medicine and Health, Sydney, NSW, Australia
  2. Department of Women’s and Children’s Health, St George Hospital, Sydney, NSW, Australia
  3. The Microbiome Research Centre, UNSW, Sydney, NSW, Australia
  4. St George and Sutherland Clinical School, UNSW Medicine and Health, Sydney, NSW, Australia

Background: A disruption to a balanced microbial ecosystem, known as dysbiosis, has been associated with multiple metabolic disorders, including gestational diabetes mellitus (GDM). However, the role of gut microbiota dysbiosis in the aetiology of GDM remains unclear, as presently, there is a deficit in longitudinal studies characterising microbiota signatures both prior to and following disease diagnosis. Thus, this study aims to investigate differences in gut microbiota composition between GDM and normoglycaemic women across all pregnancy trimesters, identifying changes in the microbiota which may predict or reflect disease onset.

Method: The gut microbiota profiles of 15 GDM (Australasian Diabetes in Pregnancy Society consensus diagnostic criteria) and 79 normoglycaemic pregnant women from the Microbiome Understanding in Maternity Study (MUMS) prospective cohort were analysed. Microbiota composition was examined via whole metagenomic shotgun sequencing of faecal samples collected from the first, second and third pregnancy trimesters. Taxonomic profiling was conducted using metagenomic phylogenetic analysis (MetaPhlan2), and resultant data was processed to identify differentially abundant taxa between GDM and normoglycaemic groups.

Results: There were no significant differences in microbiota alpha or beta diversity between GDM and normoglycaemic women (P > 0.05). However, significant differences in gut microbiota composition were detected at class and species taxonomic levels between GDM and normoglycaemic women in all pregnancy trimesters (P < 0.05). Variations in bacterial abundance between groups were identified in early pregnancy prior to GDM diagnosis and persisted in mid to late gestation. The study found that classes Gammaproteobacteria and Deltaproteobacteria, and species Bacteroides dorei, Eggerthella sp., Escherichia coli, Klebsiella oxytoca, Veillonella dispar and Bifidobacterium catenulatum were enriched in GDM compared to normoglycaemic women (P < 0.05). Conversely, class Clostridia and species Barnesiella intestinihominis, Bifidobacterium breve and Adlercreutzia equolifaciens were depleted in GDM compared to normoglycaemic women (P < 0.05). These aforementioned species were differentially abundant between groups in at least two pregnancy trimesters. Overall, there was a relative enrichment of bacteria identified as pathobionts and a depletion of bacteria recognised as commensal symbionts in the microbiota profiles of GDM compared to normoglycaemic women.

Conclusion: This study revealed that aberrations in the gut microbiota composition of women with GDM were present prior to disease diagnosis and persevered through pregnancy, suggesting an association between microbiota profile and GDM status. The microbiota signature of women with GDM should be further explored to determine its pathophysiological role and potential for use as a non-invasive predictive biomarker of the disease.