1. Department of Obstetrics and Gynecology, Unit of Reproductive Medicine, Hospitalar Center São João, Porto, Portugal;
2. Department of Clinical Epidemiology, Predictive Medicine and Public Health, Faculty of Medicine, University of Porto, Porto, Portugal;
3. EPI Unit, Institute of Public Health, University of Porto, Porto, Portugal;
4. Department of Gynecology and Obstetrics, Faculty of Medicine, University of Porto/Hospitalar Center S. João, Porto, Portugal;
5. Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal;
6. Department of obstetrics and Gynecology, Kaplan Medical Center, Rehovot, and the Hadassah-Hebrew University School of Medicine, Jerusalem, Israel