1. Department of Neurology, University Hospital Schleswig Holstein, Luebeck, Germany.
2. Kiel Migraine and Headache Centre, Kiel, Germany.
3. Department of Gynecology and Obstetrics, University Hospital Schleswig Holstein, Campus Kiel, Luebeck, Germany.
4. Department of Gynecology and Obstetrics, University Hospital Schleswig Holstein, Campus Luebeck, Luebeck, Germany.
5. Department of Gynecology and Obstetrics, Clinic Saarbrücken, Saarbrücken, Germany.