P-499 Individualization of the mean luteal phase after frozen embryo transfer with hormone replacement therapy

Abstract Study question Objective: To determine in embryo cryotransfer cycles with hormone replacement therapy whether progesterone levels five days after transfer < 15.7 ng/mL correlate with reproductive outcomes. Summary answer Conclusion: We cannot affirm that low levels of progesterone in the mid luteal phase after cryotransfer are an independent factor of evolutionary gestation. What is known already n the transfer of frozen embryos with hormone replacement therapy after a period of endometrial preparation with estrogens for 10-12 days, luteal phase support with vaginal progesterone is administered as many days as the embryo to be transferred, as reported by Van de Vijver et al 2001. After reporting that low progesterone levels on the day of transfer were associated with worse outcomes, our purpose is to evaluate progesterone levels after transfer with the first prospective study monitoring post-transfer progesterone levels to see if its supplementation correlates with better reproductive outcomes. Study design, size, duration Study desing: Analytical, observational, longitudinal, prospective study conducted at the Assisted Reproduction Unit of Hospital Quironsalud Barcelona between December 2021 and May 2022. 159 patients aged 18-42 years who have undergone a cycle of frozen embryo transfer (CT) of their own or donated embryos with hormone replacement therapy. Participants/materials, setting, methods Material and methods: Determine in embryo cryotransfer cycles with hormone replacement therapy with estradiol, luteal phase support of micronized natural progesterone five full days prior to the transfer of a blastocyst.Determination of progesterone levels five days after transfer, if levels > = 15.7ng (group C) we followed the same guideline, if =15.7ng with 65.71% CI95%[53.31,76.38] p = 0.65, and in the group of P4D+10 < 15.7 ng became pregnant 53.57% CI95%[34. 21,71.99] p = 0.53 of group A with respect to 45.90% IC95%[33.26,59.06] p = 0.45 group B. Clinical evolutionary pregnancy rat