1. Department of Obstetrics and Gynecology; Turku University Hospital; Turku; Finland
2. Department of Clinical Chemistry; University of Turku and TYKSLAB, Hospital District of Southwest Finland; Turku; Finland
3. Department of Biostatistics; University of Turku; Turku; Finland
4. Department of Medicine; University of Turku and Turku University Hospital; Turku; Finland