ObjectiveTo evaluate the effect of progesterone supplementation during the luteal phase on pregnancy outcome in natural frozen-thawed embyo transfer (FTET) cycles.MethodsIn this retrospective cohort study, 228 consecutive patients who underwent FTET cycles between January 2009 and September 2012 were included. One hundred forty-five patients received luteal progesterone support (P group) but 83 patients did not receive any progesterone supplementation during luteal phase (control group).ResultsThere were no differences in patients' characteristics between the two groups. The two groups were similar with respect to the characteristics of previous fresh in vitro fertilization cycle in which embryos were cryopreserved including the numbers of oocytes retrieved, mature oocytes, fertilized oocytes, grade 1 or 2 embryos and frozen embryos. Also, significant differences were not observed between the P and control groups in clinical pregnancy rate, embryo implantation rate and multiple pregnancy rate. However, miscarriage rate was significantly lower in the P group and live birth rate was significantly higher in the P group than in the control group (P<0.05, P<0.05).ConclusionOur results suggest that luteal phase progesterone supplementation decreases miscarriage rate and improves live birth rate in natural FTET cycles.

ObjectiveTo evaluate whether letrozole incorporated in a gonadotrophin-releasing hormone (GnRH) antagonist multiple dose protocol (MDP) improved controlled ovarian stimulation (COS) and in vitro fertilization (IVF) results in poor responders who underwent IVF treatment.MethodsIn this retrospective cohort study, a total of 103 consecutive IVF cycles that were performed during either the letrozole/GnRH antagonist MDP cycles (letrozole group, n=46) or the standard GnRH antagonist MDP cycles (control group, n=57) were included in 103 poor responders. COS results and IVF outcomes were compared between the two groups.ResultsTotal dose and days of recombinant human follicle stimulating hormone (rhFSH) administered were significantly fewer in the letrozole group than in the control group. Duration of GnRH antagonist administered was also shorter in the letrozole group. The number of oocytes retrieved was significantly higher in the letrozole group. However, clinical pregnancy rate per cycle initiated, clinical pregnancy rate per embryo transfer, embryo implantation rate and miscarriage rate were similar in the two groups.ConclusionThe letrozole incorporated in GnRH antagonist MDP may be more effective because it results comparable pregnancy outcomes with shorter duration and smaller dose of rhFSH, when compared with the standard GnRH antagonist MDP.