Received March 26, 2019
Accepted October 01, 2019

Objective: To determine the effect of fresh IVF/ICSI cycles on FET cycle embryo and pregnancy outcomes. Methods: This retrospective cohort study included data from the medical records of 104 FET cycles performed from January 2014 to December 2016. Embryos were pre- viously vitrified and then thawed for embryo transfer. Sta- tistical significance was established at p<0.05. The main endpoints were FET cycle survival and pregnancy rates. Results: A total of 104 FET cycles were analyzed for survival; 94 showed good progression and 84 achieved em- bryo transfers. Patients with secondary infertility achieved significantly higher pregnancy rates - 6/38 (15.8%) vs. 18/46 (39.1%) (p<0.018). Stimulation with FSH/LH result- ed in more significant embryo progression, 38/48 (79.2%) vs. 28/46 (60.9%) in the FSH group (p=0.01). Patients who got pregnant from fresh cycles had the highest preg- nancy rates in FET cycles (p<0.0001). Lower numbers of frozen embryos correlated with higher pregnancy rates (p=0.048). Embryos frozen on day 2 or 3 had the most significant progression (p<0.0001). Freeze-thaw intervals >12 months yielded higher pregnancy rates, 13/30 (43%), vs. 11/54 (20.4%) (p=0.025). Conclusion: Patient pregnancy in fresh cycles is a good prognostic factor for FET cycle success. Delaying FET by more than 12 months might result in higher pregnancy rates.