P–619 Oral dydrogesterone (OD) versus micronized vaginal progesterone (MVP) for luteal phase support (LPS) in IVF/ICSI: a double blind, cross-over, pharmacokinetic study

Abstract Study question How does the blood pharmacokinetic (PK) profile of OD/MVP differ after the first and last administration dose when used as LPS for fresh embryo transfer? Summary answer: The PK profile differed strongly between both LPS administration strategies with a more rapid absorption, metabolism and clearance of OD in comparison with MVP. What is known already Adequate LPS is crucial to achieve a successful pregnancy following ovarian stimulation (OS) and fresh embryo transfer. OD has been proven to be non-inferior compared to MVP in two phase III clinical trials. Additionally, a combined individual participant data and aggregate data meta-analysis showed an odds ratio in favor of OD for live birth. Little information is available on the PK of LPS strategies, leaving an important field unexplored. Individualization of LPS has recently gained more interest and insight into the PK of progestogens is essential to correctly interpret the potential impact of circulating hormone levels on reproductive outcomes. Study design, size, duration Twenty oocyte donors underwent two OS cycles followed by one week of LPS (OD or MVP) in a randomized, cross-over, double blind, double dummy fashion. As both dydrogesterone (D) and 20αdihydrodydrogesterone (DHD) are progestogenic, D, DHD and progesterone (P) plasma levels were established using a validated liquid chromatography tandem mass spectrometry assay in each cycle, on the 1st (single dose PK) and 8th day (multiple dose PK) of LPS (9 and 12 harvesting time-points, respectively). Participants/materials, setting, methods All oocyte donors were