1. Department of Obstetrics and Gynaecology, University of Helsinki and Helsinki University Hospital , Helsinki, Finland
2. Human Microbiome Research Program, Faculty of Medicine, University of Helsinki , Helsinki, Finland
3. Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London , London, United Kingdom
4. Department of Obstetrics and Gynaecology, Oulu University Hospital , Oulu, Finland
5. Medical Research Center, Oulu University Hospital and University of Oulu , Oulu, Finland