Background The maternal microbiome has been implicated in the development of preeclampsia. Here, we comprehensively define the oral, vaginal, and gut microbiomes of women with preeclampsia and their infants and compare them with normotensive controls in the US.

Methods Women with and without preeclampsia were recruited during delivery. Oral, vaginal, and gut samples were collected before rupture of membranes in women planning a vaginal delivery. Infant stool samples were collected during the first week of life. Microbiome profiling was performed using 16S rRNA gene sequencing for oral, vaginal, and infant stool and shotgun metagenomic sequencing for maternal stool. We performed microbiome analyses comparing groups with and without preeclampsia and those with and without severe features of preeclampsia.

Results We recruited 49 and 51 women with and without preeclampsia, respectively. Women with preeclampsia exhibited lower oral microbial richness, distinct composition, and greater interindividual variability than controls. Higher oral microbiome diversity during delivery correlated with lower blood pressure postpartum, regardless of preeclampsia status. Infants of mothers with severe preeclampsia were depleted of gut Bifidobacterium. Other differences in the microbiomes emerged after stratification by ethnicity. Hispanic women with preeclampsia exhibited reduced oral richness and shifts in oral nitrate-reducing taxa; reduced vaginal richness and decreased abundance of vaginal Lactobacillus jensenii; and depletion of Clostridia species and Akkermansia in the gut.

Conclusions Preeclampsia was associated with alterations in the maternal oral, vaginal, and gut microbiomes, depending on the mother’s ethnicity. Infants born to women with preeclampsia exhibit a reduction in the abundance of beneficial Bifidobacterium.

The authors have declared no competing interest.

This was not a clinical trial but an observational study

This work was funded by a Novice Researcher Grant awarded to Dr. Courtney Birchall by The Gerber Foundation. The Gerber Foundation did not play a role in study design, analysis planning, or manuscript development.

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UMass Chan Institutional Review Board (Docket # H00020140)

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