“…Progestogens are usually administered using intravaginal devices, including silicone-based devices impregnated with progesterone (P4), such as Controlled Internal Drug Release (CIDR) and Dispositivo Intravaginal Caprino Ovino (DICO) ( Wheaton et al, 1993 ; Vilariño et al, 2010 ), or, intravaginal sponges (IVS) impregnated with progesterone analogues, as medroxyprogesterone acetate (MAP) or flurogestone acetate (FGA) ( Barrett et al, 2008 ; Santos et al, 2010 ). There are some preliminary studies on the administration of long-acting injectable progesterone ( Rodríguez-Martínez et al, 2018 ; Alvarado-Espino et al, 2019 ; Amaral D’Avila et al, 2022 ; Payan et al, 2022 ), but the results are still inconsistent. Until now, sponges impregnated with MAP have been used for the resynchronization protocol ( Miranda et al, 2018 ; Cosentino et al, 2019 , 2021 , 2022 ), but to the best of our knowledge, there are no studies with other progestogens.…”