The true natural cycle frozen embryo transfer - impact of patient and follicular phase characteristics on serum progesterone levels one day prior to warmed blastocyst transfer. - Mumusoglu, Sezcan; Erden, Murat; Ozbek, Irem Yarali; Ince, Onur; Esteves, Sandro C.; Humaidan, Peter; Yarali, Hakan (Reproductive Biology & Endocrinology, 2023)