Antenatal Microbiome Potential Contributor to Fetal Programming and Establishment of the Microbiome in Offspring Michelle L. Wright ▼ Angela R. Starkweather Background: Endogenous and exogenous exposures during fetal development have potential to impact birth and health outcomes of offspring. Accumulating evidence suggests exposures may alter the antenatal microbiome and subsequently alter the microbiome and health of offspring. Objectives: The purpose of this integrative review is to summarize and critically evaluate the current state of knowledge regarding the assessment of the antenatal microbiome on the health of human offspring. The article provides a brief summary of the known factors affecting the human microbiome and studies that assessed relationships between the antenatal microbiome and health outcomes of the offspring. Methods: An integrative review was conducted to examine human research studies that focused on the antenatal microbiome and the health of the offspring using the electronic databases PubMed/MEDLINE and CINAHL from 2004 to the present. Results: In addition to the known individual factors that are associated with establishment of the microbiome, the results of the integrative review suggest that medications (including antibiotics) and comorbidities (including infectious diseases, diet, socioeconomic status, and exposure to pollutants) should also be measured. Discussion: The composition of the antenatal microbiome at various time points and body sites may be important mediators of short- and long-term health outcomes in offspring. In order to advance our understanding of the role of the antenatal microbiome on health and disease risk of the offspring, it will be important to further elucidate the composition of a healthy microbiome and specific mechanisms that contribute to altered health in later life. Key Words: antenatal  microbiome  microbiota  neonate Nursing Research, Month 2015, Vol 00, No 0, 00–00 F etal development is a period of unparalleled cellular pro- liferation, tissue formation, and organ construction within the confines of the womb—a human incubator that sur- rounds the fetus with amniotic fluid and provides nourishment for growth and protection of vulnerable tissues (Agin, 2009). Although historically the womb and fetus have been considered sterile until birth or rupture of the amniotic sac, recent evidence shows that the womb is host to a diversity of microorganisms that closely resemble the mother’ s oral microbial community (Aagaard et al., 2014; DiGiulio et al., 2008). In addition, nutrient exchange that occurs through active and passive transport from the mother’s circulation to the placenta—an organ that acts as a selective maternal–fetal barrier—can also include toxins and microbes that can gain direct entry into fetal circulation. Thus, microbes from the placenta, amniotic fluid, and umbilical cord blood provide a diverse array of exposures to the developing fetus. For this reason, evaluation of the antenatal microbiome (microbial composition at multiple sites during pregnancy) may provide insight into the developmental origins of disease that have not been identified. The purposes of this article are to (a) briefly introduce the microbiome, the antenatal microbiome, and the microbiome and fetal programming; (b) present findings from an integrative review designed to summarize and critically evaluate the current state of knowledge regarding the antenatal microbiome and the health of human offspring; and (c) discuss findings in light of implications for nursing science. The Microbiome The microbiome (the community of microorganisms, including bacteria, fungi, and viruses, which reside upon and within the human body) has gained attention as an important modulator of health and disease (Moloney, Desbonnet, Clarke, Dinan, & Cryan, 2014). Researchers have characterized a unique “core” microbiome inhabiting the skin, mouth, gut, urogenital tract, and vagina of adults (The Human Microbiome Project Consortium, Michelle L. Wright, PhD, RN, is Postdoctoral Nurse Scholar, Virginia Common- wealth University School of Nursing, Richmond. Angela R. Starkweather, PhD, ACNP-BC, CNRN, is Associate Professor and Chair, Department of Adult Health and Nursing Systems, Virginia Commonwealth University School of Nursing, Richmond. DOI: 10.1097/NNR.0000000000000101 Biology Review Series Nursing Research www.nursingresearchonline.com 1 Copyright © 2015 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.