BACKGROUND: The gut microbiota plays a role in maintaining human health and in the development or prevention of illness partially through the release of metabolites. Throughout pregnancy, physiological changes to hormonal, immunological and cardiovascular systems and metabolic regulation are required to sustain fetal growth. In early pregnancy, the capacity of the gut microbiota to produce the short chain fatty acid (SCFA) butyrate is inversely correlated with systolic blood pressure. However, it is unclear if the gut microbiota composition is altered in women developing hypertension or preeclampsia later in pregnancy. In the present study, we investigate gut microbiota composition at 28 weeks gestation between women who go on to develop preeclampsia and non-hypertensive pregnant controls.
METHODS: The composition of gut microbiota was investigated by 16S rRNA sequencing of faecal samples obtained from pregnant women in the SPRING cohort (Study of Probiotics IN gestational diabetes) at 28 weeks gestation. Gut microbiota composition was compared between pregnant women who developed preeclampsia (n=11) and controls (n=200). Quantitative real-time PCR was used to assess the density of butyrate-producing genes.
RESULTS: Women who develop preeclampsia had significantly decreased abundance of the genera Coprococcus, Parabacteroides, Roseburia, Unclassified Christensenellaceae and Unclassified Clostridiales. Abundance of the Coprococcus genus, which is known to express butyrate-producing genes, is significantly positively correlated with the gene density of the butyrate genes BUT and BUK and total butyrate-production.
DISCUSSION: The results suggest that reduced abundance of butyrate-producing bacteria contributes to increased risk of preeclampsia in pregnant women.