The Human Microbiome before Birth Martin J. Blaser, Maria G. Dominguez-Bello  Cell Host & Microbe  Volume 20, Issue 5, Pages 558-560 (November 2016) DOI: 10.1016/j.chom.2016.10.014 Copyright © 2016 Elsevier Inc. Terms and Conditions

Figure 1 Schematic of Pregnancy, Including Microbiota, Immune Responses, and Perturbations During pregnancy, there are changes in immune and hormonal function, and the vaginal and intestinal microbiota show progressive maturation to the “climax” of birth. There is likely bi-directional microbiota and host immunologic/hormonal interaction, with secondary effects on the pre-partum breast (all physiologic processes shown in green). At birth, the altered microbial communities are transferred to the baby, as has occurred throughout mammalian evolution. Antibiotic exposures pre-partum could affect both maternal microbiota compositions with downstream effects on immunological/hormonal effectors and microbial transmission. Antibiotic exposures of the fetus peri-partum and the infant post-partum differentially select for the initial colonizing bacteria, as does formula feeding. Post-partum exposures of mother to antibiotics affect their own transmissible microbiota and lead to infant exposures by breast milk. Cesarean section thwarts the transmission of the climax vaginal and intestinal microbial communities to the infant and usually also involves antibiotic dosing. All causes of perturbations are shown in orange. Swabbing of babies with maternal vaginal fluids (pink) can partially restore the ancestral microbiota. Cell Host & Microbe 2016 20, 558-560DOI: (10.1016/j.chom.2016.10.014) Copyright © 2016 Elsevier Inc. Terms and Conditions