1. Follicle Biology Laboratory (FOBI), UZ Brussel, Vrije Universiteit Brussel, Laarbeeklaan 101, Brussels 1090, Belgium
2. Current address: Centro de Estudios e Investigaciones en Biología y Medicina Reproductiva—BIOMER, Lima, Peru
3. Centre for Reproductive Medicine, UZ Brussel, Vrije Universiteit Brussel, Laarbeeklaan 101, Brussels 1090, Belgium