Acknowledgements
First of all we would like to thank all participating women for their time and effort in this study. Furthermore, we would like to thank the Dutch and Belgian endometriosis foundation for their support in recruiting women for this study. And finally we would like to thank the following participating centers: UMC Groningen (dr. Ellen Klinkert), Medisch Spectrum Twente (drs. Laurens van Boven), Catharina Ziekenhuis (Prof. dr. Dick Schoot), Isala clinic (dr. Joke Schutte), Rijnstate hospital (Prof. dr. Annemiek Nap), VUmc (Prof. dr. Velja Mijatovic), MUMC (dr. Lennie van Hanegem), Bravis hospital (dr. Marja Noordam), Radboud UMC (dr. Bertho Nieboer), OLVG (dr. Paul van Kesteren), Erasmus MC (dr. Anneke Steensma).