1. Department of Gynecology; Medical University of Białystok; Białystok; Poland
2. Frauenklinik und Brustzentrum; Ostalb-Klinikum Aalen; Akademisches Lehrkrankenhaus der Universität Ulm; Germany
3. Division of Perinatal Medicine; Department of Pediatrics; University of Colorado Denver; Aurora; Colorado
4. Department of Reproductive Health; National Research Institute of Mother and Child; Warsaw; Poland