Fig. 2. Co-occurrence of vaginal microbiota in early pregnancy in the context of secretor status. (a) Co-occurrence networks of early pregnancy vaginal microbiota in secretors and non-secretors. Nodes represent bacterial taxa detected at >0.5% relative abundance in two or more samples and have been grouped into L. crispatus, L. gasseri, L. iners, L. jensenii, other Lactobacillus, BV-associated bacteria, pathobionts and others, as defined previously. Statistically significant edges, indicating correlations, are coloured and weighted according to their r value: red (negative correlation); green (positive correlation). In both secretors and non-secretors, many positive associations were observed between BV-associated microbes. (b) Star diagrams (derived from the network analyses) centred on the L. crispatus, L. iners and G. vaginalis nodes indicate Lactobacillus species, especially L. crispatus, tend to be more negatively correlated with other bacteria in the vaginal microbiota of both secretors and non-secretors, compared with G. vaginalis and other BV-associated bacteria.