1. Department of Obstetrics and Gynaecology, University Hospital of Araba, Vitoria-Gasteiz, Spain;
2. Bmum Clinic, Madrid, Spain;
3. Department of Obstetrics and Gynaecology, Associated University Hospital of Requena, Requena, Spain;
4. Department of Obstetrics and Gynaecology, University Hospital of Guadalajara, Guadalajara, Spain;
5. Euskalduna Clinic, Bilbao, Spain;
6. Department of Obstetrics and Gynaecology, Hospital Virgen Macarena, Seville, Spain;
7. Unit of Sexual and Reproductive Health, Campoamor, Spain;
8. Diatros Clinic, Barcelona, Spain