Abstract : The problem of an excessive number of embryos being produced now has only one remedy, and that is the cryopreservation of embryos. Even though fresh endometrial tissue is typically used in assisted reproductive technologies (ART). To evaluate if progesterone P4 monitoring prior to and on the day of frozen embryo transfer can accurately predict pregnancy outcome. This is a cross-sectional observational study of 50 infertile women. Follow-up was done until the foetal heart was positive. Blood samples were obtained the day before and the day of embryo transfer in frozen cycles to assess serum progesterone p4. One day before embryo transfer, samples were obtained. Endometrial preparation uses standardised HRT. The pregnancy rate among all infertile women who participated in the trial was 35.7%. Age, BMI, infertility etiology, and embryo grade were not associated with hormonal monitoring. Individuals with low blood P4 levels the day before FET may benefit from daily intramuscular P4 injections if they are started the day before FET, and their reproductive success is comparable to that of patients with appropriate P4 levels to begin with. Prior to embryo transfer, monitoring progesterone levels revealed a substantial difference, with a P4the threshold level of 11.6ng/ml. Monitoring blood progesterone levels the day before and the day of embryo transfer improves pregnancy chances. Individualized luteal phase support (Ilps) provided the day before embryo transfer may increase the chance of a successful pregnancy.