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

STUDY QUESTION: Does the type of luteal support affect pregnancy outcomes in recipients of vitrified blastocysts? SUMMARY ANSWER: Luteal support with vaginal progesterone gel or i.m. progesterone (IMP) results in comparable implantation and pregnancy rates in IVF patients receiving vitrified blastocysts. WHAT IS KNOWN ALREADY: In fresh IVF cycles, both IMP and vaginal progesterone have become the standard of care for luteal phase support. Due to conflicting data in replacement cycles, IMP is often considered to be the standard of care. STUDY DESIGN, SIZE, DURATION: Retrospective analysis of 920 frozen embryo transfer (FET) cycles between 1 January 2010 and 1 September 2012. 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 = 0.81), clinical pregnancy rates (61.7 versus 60.5%, P = 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 FOR CAUTION: 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. WIDER IMPLICATIONS 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. STUDY FUNDING/COMPETING INTEREST(S): Support for data collection and analysis was provided by Actavis, Inc. D.S. has received honoraria for lectures and participation in Scientific Advisory Boards for Actavis, Inc. J.P. is an employee of Actavis, Inc. N.E. has received payment from Actavis, Inc., for her time for data collection. H.H. has received payment from Actavis, Inc., for statistical analyses. Z.P.N. has nothing to disclose.