1. Oxford Fertility, Institute of Reproductive Sciences, Oxford OX4 2HW, UK
2. Nuffield Department of Women’s & Reproductive Health, University of Oxford, Oxford OX3 9DU, UK
3. Nuffield Department of Women's & Reproductive Health, Endometriosis Care and Research Centre, University of Oxford, Oxford OX3 9DU, UK
4. Nuffield Department of Orthopaedics, Centre for Statistics in Medicine, Botnar Research Centre, Rheumatology & Musculoskeletal Sciences, University of Oxford, Oxford, UK
5. Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK