1. Department of Medical Epidemiology and Biostatistics; Karolinska Institutet; Stockholm Sweden
2. Department of Women's and Children's Health; Karolinska Institutet; Stockholm Sweden
3. Division of Obstetrics and Gynecology; Karolinska University Hospital; Stockholm Sweden
4. Department of Clinical Sciences; Karolinska Institutet Danderyd Hospital, Karolinska Institutet; Stockholm Sweden
5. Department of Statistics and Quantitative Methods; University of Milano-Bicocca; Milan Italy