Effectiveness, safety, and practicality of intramuscular progesterone in restoring pregnancy outcomes during frozen embryo transfers. - Nguyen CN; Nguyen TTN; Le TT; Vu PB; Le LTP; Pham NB; To HM; Nguyen XT; Nguyen LTT; Nguyen VTC; Pham YTK; Tran TH; et al. (Frontiers in endocrinology, 2025)