Vargas, Mireia, Yañez, Francisca, Elias, Andrea, Bernabeu, Andrea, Goya, M, Xie, Zixuan, Farràs Llobet, Alba, Sánchez Martínez, M. Olga, Soler, Zaida, Blasquez, Carlos, Valle, Leonor, Olivella, Anna, Muñoz, Begoña, Brik, Maia, Carreras Moratonas, Elena, Manichanh, Chaysavanh, Universitat Autònoma de Barcelona, Institut Català de la Salut, [Vargas M, Farrás A] Servei d’Obstetrícia i Medicina Reproductiva, Unitat de Medicina Fetal, Vall d'Hebron Hospital Universitari, Barcelona, Spain. Universitat Autònoma de Barcelona, Bellaterra, Spain. [Yañez F, Elias A, Xie Z, Manichanh C] Maternal and Child Health and Development Network (SAMID), Instituto de Salud Carlos III, Madrid, Spain. [Bernabeu A] Servei d’Obstetrícia i Medicina Reproductiva, Unitat de Medicina Fetal, Vall d'Hebron Hospital Universitari, Barcelona, Spain. Universitat Autònoma de Barcelona, Bellaterra, Spain. Department of Reproductive Medicine, Instituto Bernabeu, Alicante, Spain. [Goya M, Carreras E] Servei d’Obstetrícia i Medicina Reproductiva, Unitat de Medicina Fetal, Vall d'Hebron Hospital Universitari, Barcelona, Spain. Universitat Autònoma de Barcelona, Bellaterra, Spain. Laboratori de Microbioma, Vall d'Hebron Hospital Universitari, Barcelona, Spain. Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Barcelona, Spain. Departament de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Spain. [Sánchez O] Laboratori de Microbioma, Vall d'Hebron Hospital Universitari, Barcelona, Spain. Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Barcelona, Spain. Departament de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Spain. Women and Perinatal Health Research Group, Institut d'Investigació Biomèdica de Sant Pau (IIB-Sant Pau). Hospital Universitari de Sant Pau, Barcelona, Spain, and Vall d'Hebron Barcelona Hospital Campus
Cervical length; Microbial diversity; Pessary Longitud cervical; Diversidad microbiana; Pesario Longitud cervical; Diversitat microbiana; Pessari Introduction Our objective was to compare the vaginal microbiome in low-risk and high-risk pregnant women and to explore a potential association between vaginal microbiome and preterm birth. Material and methods A pilot, consecutive, longitudinal, multicenter study was conducted in pregnant women at 18–22 weeks of gestation. Participants were assigned to one of three groups: control (normal cervix), pessary (cervical length ≤25 mm) and cerclage (cervical length ≤25 mm or history of preterm birth). Analysis and comparison of vaginal microbiota as a primary outcome was performed at inclusion and at 30 weeks of gestation, along with a follow-up of pregnancy and perinatal outcomes. We assessed the vaginal microbiome of pregnant women presenting a short cervix with that of pregnant women having a normal cervix, and compared the vaginal microbiome of women with a short cervix before and after placement of a cervical pessary or a cervical cerclage. Results The microbiome of our control cohort was dominated by Lactobacillus crispatus and inners. Five community state types were identified and microbiome diversity did not change significantly over 10 weeks in controls. On the other hand, a short cervix was associated with a lower microbial load and higher microbial richness, and was not correlated with Lactobacillus relative abundance. After intervention, the cerclage group (n = 19) had a significant increase in microbial richness and a shift towards community state types driven by various bacterial species, including Lactobacillus mulieris, unidentified Bifidobacterium or Enterococcus. These changes were not significantly observed in the pessary (n = 26) and control (n = 35) groups. The cerclage group had more threatened preterm labor episodes and poorer outcomes than the control and pessary groups. Conclusions These findings indicate that a short cervix is associated with an altered vaginal microbiome community structure. The use of a cerclage for preterm birth prevention, as compared with a pessary, was associated with a microbial community harboring a relatively low abundance of Lactobacillus, with more threatened preterm labor episodes, and with poorer clinical outcomes. This study was supported by the Instituto de Salud Carlos III/FEDER FIS PI15/02043; Beca Dexeus Mujer 2015. Francisca Yáñez was supported by a grant from ANID, BECAS Chile, N° 72190278. Zixuan Xie received a fellowship from the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie Action, Innovative Training Network: FunHoMic; grant number 812969.