# Source of the Placental Microbiome

> **NIH NIH R01** · BAYLOR COLLEGE OF MEDICINE · 2020 · $668,167

## Abstract

Human-associated microorganisms (the “microbiome”) are present in numbers exceeding the quantities of
human cells by at least 10-fold, and the collective genome (the “metagenome”) exceeds our human genome
in terms of gene content by more than 150-fold. We and others have recently demonstrated that bacteria are
detected in the placenta using a variety of culturable and non-culturable approaches. For several years we
have developed and employed metagenomics to characterize the placental microbiome, and observed
variation in its community membership and their function by virtue of gestational age at delivery. However, it
remains unknown what the different maternal source(s) are of the placental microbiome, and whether it sinks
to the fetus via the intra-amniotic cavity and thus is measureable in amniotic fluid.
 In response to the Human Placental Project, we propose to identify the sources and sinks for and of the
placental microbiome employing two large, robust and well characterized existing datasets. We will generate
unparalleled metagenomics and metabolomics data, in order to test our central hypothesis that the placenta is
populated by commensal microbiota which largely arise from the maternal oral and GI communities, with a
lesser contribution from the vagina. We further hypothesize that placental microbes populate the fetus and the
intrauterine environment, and are detectable in mid-trimester amniotic fluid. Moreover, their metabolites serve
as lasting signatures of the microbiotas functional presence.
 In order to prove this hypothesis, we will execute three essential aims in a total of over 1230 subjects
samples from two existing data sets. The net result of the completion of these aims will be to first identify the
maternal source of the placental microbiota, and validate these findings using state of the art single molecule
fluorescent in situ hybridization and culturation. We will thereafter recapitulate these findings in early and mid-
second trimester amniotic fluid and thus identify the early evidence of the placental microbiota sink. In a final
aim, we will use LC/MS full spectral metabolomics on these same subjects samples to identify the stable and
lasting metabolic footprint of the microbiome. We present our proof of concept work on intrahepatic cholestasis
of pregnancy as evidence for the feasibility, significance and ready translational application of our approach.
 As a proven team of perinatal physician scientists with an emphasis and history of being at the forefront of
big data (and notably metagenomics) science, we are uniquely poised to now undertake complex integration of
these unique data sets in studies which are feasible, justifiable, and of likely long-term significance and high
impact.

## Key facts

- **NIH application ID:** 9855012
- **Project number:** 5R01HD091731-04
- **Recipient organization:** BAYLOR COLLEGE OF MEDICINE
- **Principal Investigator:** Kjersti Marie Aagaard
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $668,167
- **Award type:** 5
- **Project period:** 2017-03-10 → 2022-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9855012

## Citation

> US National Institutes of Health, RePORTER application 9855012, Source of the Placental Microbiome (5R01HD091731-04). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9855012. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*