Progesterone replacement with vaginal gel versus i.m. injection: cycle and pregnancy outcomes in IVF patients receiving vitrified blastocysts

participants/materials, setting, methods: Patients from a large, private practice undergoing autologous and donor FET using IMP or vaginal progesterone gel for luteal support were included in the analysis. IMP was used for luteal support in 682 FET cycles and vaginal progesterone gel was used in 238 FET cycles. Standard clinical outcomes of positive serum hCG levels, implantation, clinical pregnancy, spontaneous abortion and live birth were reported. main results and the role of chance:The IMP and vaginal progesterone gel groups had similar patient demographics for all characteristics assessed. Implantation rates (46.4 versus 45.6%, P ¼ 0.81), clinical pregnancy rates (61.7 versus 60.5%, P ¼ 0.80) and live birth rates (49.1 versus 48.9%, P . 0.99) were not significantly different between IMP and vaginal progesterone gel, respectively. limitations, reasons forcaution: This study is limited by its retrospective design and by its lack of randomization to the type of luteal support. In addition, because no a priori expected rates of success could be provided for this retrospective investigation, it was not possible to estimate statistical power associated with the various outcomes presented. widerimplications of the findings: With the recent trends toward single embryo transfer (SET) and use of vitrified blastocysts in FET cycles, our data with � 40% of cycles being SET and use of exclusively vitrified blastocysts are more relevant to current practices than previous studies.