Administration of progesterone before oocyte retrieval negatively affects the implantation rate

Crinone vaginal gel is equally effective and better tolerated than intramuscular progesterone for luteal phase support in in vitro fertilization–embryo transfer cycles: a prospective randomized study

“…When Crinone was started within 24 hours after egg retrieval, the pregnancy rates were noted to be lower (8,14), whereas if Crinone was started between 36 to 72 hours after egg retrieval, the pregnancy rates were similar (9,12). Lower pregnancy rates with IMP also have been observed when IMP was administered too early in the cycle-that is, before egg retrieval compared with within 24 hours after egg retrieval (20). These results could be explained by accelerated advancement of the endometrium and premature closure of the implantation window.…”

Comparison of live-birth defects after luteal-phase ovarian stimulation vs. conventional ovarian stimulation for in vitro fertilization and vitrified embryo transfer cycles

“…Sohn et al (26) found that exposure of the oocyte to P in vivo had a significant adverse effect on implantation rate. Others found that the addition of P to cumulus oocyte complexes reduced, by approximately 40%, the proportion of both total oocytes and cleaved oocytes that reached the blastocyst stage.…”

Early progesterone cessation after in vitro fertilization/intracytoplasmic sperm injection: a randomized, controlled trial

“…Progesterone (P) supplementation is suspended around positive b-hCG (5,6) or extended up to 8 weeks (7,8) or 12 weeks of pregnancy (2,(9)(10)(11)(12)(13). Because the luteal-placental shift happens around week 7-8, traditionally LPS has been maintained until then, with the added benefit that exogenous P has seemed to be a risk-free drug.…”