Stability of the vaginal, oral, and gut microbiota across pregnancy among African American women: the effect of socioeconomic status and antibiotic exposure

• Published in: PeerJ (San Francisco, CA) CA), 2019-11, Vol.7, p.e8004, Article e8004
• Main Authors: Dunlop, Anne L, Knight, Anna K, Satten, Glen A, Cutler, Anya J, Wright, Michelle L, Mitchell, Rebecca M, Read, Timothy D, Mulle, Jennifer, Hertzberg, Vicki S, Hill, Cherie C, Smith, Alicia K, Corwin, Elizabeth J
• Format: Article
• Language: English
• Subjects: African American women; African Americans; Antibiotics; Biodiversity; Birth; Education; Epidemiology; Ethnicity; Genes; Genomics; Gynecology and Obstetrics; Insurance; Intestinal microflora; Mediation; Medical personnel training; Microbiology; Microbiome; Microbiota; Microbiota (Symbiotic organisms); Microorganisms; Multiculturalism & pluralism; Pregnancy; Pregnant women; Premature birth; Premature infants; Prenatal experience; Race; Regression analysis; RNA; rRNA 16S; Social class; Socioeconomic factors; Studies; Vagina; Women; Womens health; Women’s Health
• ISSN: 2167-8359; 2167-8359
• DOI: 10.7717/peerj.8004

A growing body of research has investigated the human microbiota and pregnancy outcomes, especially preterm birth. Most studies of the prenatal microbiota have focused on the vagina, with fewer investigating other body sites during pregnancy. Although pregnancy involves profound hormonal, immunological and metabolic changes, few studies have investigated either shifts in microbiota composition across pregnancy at different body sites or variation in composition at any site that may be explained by maternal characteristics. The purpose of this study was to investigate: (1) the stability of the vaginal, oral, and gut microbiota from early (8-14 weeks) through later (24-30 weeks) pregnancy among African American women according to measures of socioeconomic status, accounting for prenatal antibiotic use; (2) whether measures of socioeconomic status are associated with changes in microbiota composition over pregnancy; and (3) whether exposure to prenatal antibiotics mediate any observed associations between measures of socioeconomic status and stability of the vaginal, oral, and gut microbiota across pregnancy. We used paired vaginal, oral, or gut samples available for 16S rRNA gene sequencing from two time points in pregnancy (8-14 and 24-30 weeks) to compare within-woman changes in measures of alpha diversity (Shannon and Chao1) and beta-diversity (Bray-Curtis dissimilarity) among pregnant African American women (  = 110). Multivariable linear regression was used to examine the effect of level of education and prenatal health insurance as explanatory variables for changes in diversity, considering antibiotic exposure as a mediator, adjusting for age, obstetrical history, and weeks between sampling. For the oral and gut microbiota, there were no significant associations between measures of socioeconomic status or prenatal antibiotic use and change in Shannon or Chao1 diversity. For the vaginal microbiota, low level of education (high school or less) was associated with an increase in Shannon and Chao1 diversity over pregnancy, with minimal attenuation when controlling for prenatal antibiotic use. Conversely, for within-woman Bray-Curtis dissimilarity for early compared to later pregnancy, low level of education and prenatal antibiotics were associated with greater dissimilarity for the oral and gut sites, with minimal attenuation when controlling for prenatal antibiotics, and no difference in dissimilarity for the vaginal site. Measures of maternal socioeconom