Oral Presentation Society of Obstetric Medicine of Australia and New Zealand and Australasian Diabetes in Pregnancy Society Joint Scientific Meeting 2017

Women who develop hypertensive disorders of pregnancy have altered composition of the gut microbiota at 16 weeks gestation (#22)

Luisa F Gomez Arango 1 , Helen L Barrett 1 2 , Leonie K Callaway 1 2 , David McIntyre 3 4 , Mark Morrison 5 , Marloes Dekker Nitert 1 6 7
  1. UQ Centre for Clinical Research, The University of Queensland, Herston, QLD, Australia
  2. Obstetric Medicine, Royal Brisbane and Women's Hospital, Herston, QLD, Australia
  3. School of Medicine, The University of Queensland, Herston, QLD, Australia
  4. Obstetric Medicine, Mater Health Services, South Brisbane, QLD, Australia
  5. Diamantina Institute, The University of Queensland, Woolongabba, QLD, Australia
  6. University of Queensland, St Lucia, QLD, Australia
  7. School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, Australia

Introduction: The gut microbiota has recently been identified as a regulator of blood pressure in early pregnancy. It is not clear whether women who develop hypertensive disorders of pregnancy (HDP) already have an altered composition of the gut microbiota in early pregnancy.

Objective: The aim of this study was to compare the composition of the gut microbiota at 16 weeks gestation between women who develop HDP with those who remained normotensive.

Patients and Methods: Women who participated in the SPRING (Study of PRobiotics IN Gestational diabetes) RCT were grouped based on a clinical diagnosis of HDP. DNA isolated from stool samples obtained at 16 weeks gestation were sequenced by 16S rRNA sequencing and analysed with the QIIME software suite. Network analysis of the gut microbiota composition was performed.

Results: Women who developed HDP later in pregnancy (n=30) already had higher systolic (P = 0.025) and diastolic (P = 0.033) blood pressure than normotensive women (n=170) at 16 weeks gestation. The women who developed HDP tended to have a higher BMI (P = 0.10) and higher dietary fibre intake (P = 0.08) but similar fasting glucose levels (P = 0.25). While the groups did not differ in alpha diversity, the overall composition of the gut microbiota was significantly different between the groups (R = 0.101; P = 0.049). Network analysis identified a higher abundance of the genera Collinsella, Ruminococcus, Acidaminococcus, Bifidobacteria, Haemophilus and Megasphaera in the HDP group.

Conclusion: Women who develop HDP later in their pregnancy have a gut microbiota that is dominated by carbohydrate fermenters. These bacteria have not previously been associated with hypertension but are more abundant in obese individuals outside pregnancy.