The effect of secretor status and the vaginal microbiome on birth outcome

Mutations in the FUT2 gene that result in a lack of expression of histo-blood group antigens on secreted glycoproteins may shape the vaginal microbiota with consequences for birth outcome. To test this, we analysed the relationship between secretor status, vaginal microbiota and gestational length in an ethnically diverse cohort of 313 pregnant women, including 91 who delivered prematurely. Lactobacillus species were found to co-occur less often with other microbial taxa in non-secretors. Moreover, non-secretors with Lactobacillus spp. depleted vaginal microbiota in early pregnancy had significantly shorter gestational length than Lactobacillus spp. dominated non-secretors (mean of 245.5 (SD=44.5) versus 265.9 (23.6)); p=0.045), but not compared to Lactobacillus spp. dominated (261.8 (27.5)) and depleted (264.3 days (21.2)) secretors. In identifying a relationship between blood-group antigen expression and vaginal microbiota-host interactions, our results point towards stratification by secretor status as an important factor for considering preterm birth risk and prevention.