Characterizing vaginal microbiome network dynamics across menstrual cycle phases and contraceptive methods

Sammanfattning

The vaginal microbiome is a dynamic ecosystem that plays a central role in the overall health of women and is susceptible to hormonal changes that occur naturally during the menstrual cycle as well as those induced by hormonal contraceptives. The imbalance of the vaginal microbiota is known as dysbiosis and can lead to gynecological disorders with detrimental consequences for fertility and pregnancy outcomes. The reported effects of combined oral contraceptives (COC) and levonorgestrel – intrauterine device (IUD) remain contradictory. In our study, we implement a novel method called LUPINE (LongitUdinal modelling with Partial least squares regression for NEtwork inference), that infers microbial networks while taking into account information from previous time-points, rather than from a single time-point. Our goal is to infer microbial networks for each menstrual phase cycle (menstrual, follicular and luteal) of three different birth control groups (non hormonal, COC, IUD) in order to study the interactions among taxa and assess the influence of different hormonal birth controls in the vaginal microbiome of healthy women of reproductive age. The three COC phases networks exhibited substantial similarity to one another but they were markedly distinct from the NHC and IUD networks, which clustered together. Conversely, the three IUD phase networks showed the greatest inter-phase dissimilarity. LUPINE revealed the contrasting effects of COC and IUD in the VMB across the menstrual cycle. COC users exhibited a more regular cycle with minimal fluctuations among the phases, yet their networks differed significantly from those of NHC users. In contrast, the phases of IUD users were highly dissimilar to one another, but the overall cycle resembled more to a natural cycle.