1. Aristotle University of Thessaloniki; Second Department of Obstetrics and Gynaecology; 92 Tsimiski Street Thessaloniki Greece 546 22
2. University Hospital of Ioannina; Department of Obstetrics and Gynaecology; Panepistimiou Avenue Ioannina Greece 45500
3. Cyprus University of Technology; Cyprus International Institute for Environmental and Public Health; Limassol Cyprus
4. Department of Medicine and Department of Health Research and Policy; Stanford Prevention Research Center; Stanford University School of Medicine Palo Alto California USA
5. The University of Auckland; Liggins Institute; Auckland New Zealand