Delaying the initiation of progesterone supplementation results in decreased pregnancy rates after in vitro fertilization: a randomized, prospective study

Objective: To compare lVF outcome between two protocols for luteal phase Su pplementation, one beginning on day 3 after oocyte retrieval and the other beginning on day 6 after retrieval. Design: Prospective, randomized study. Setting: University-based assisted reproductive technology center. Patient(s): One hundred twenty-six consecutive patients undergoing TVF betw een January and July 2000. Intervention(s): Patients were randomized to be-in luteal phase support usi ng vaginal progesterone beginning either on day 3 after oocyte retrieval or on day 6 after oocyte retrieval. Main Outcome Measure(s): Clinical pregnancy rates and implantation rates. Result(s): All patients randomized underwent transfer. There were no differ ences in age, oocytes retrieved, or embryos transferred between the two gro ups. Those patients receiving luteal phase support with progesterone beginn ing on day 6 after retrieval had a significantly lower clinical pregnancy r ate per transfer compared with those beginning support on day 3 after retri eval (44.8% vs. 61.0%, respectively). This difference in pregnancy rates wa s greater in those patients undergoing a luteal gonadotropin releasing horm one (GnRH) agonist down-regulation protocol (47.5% vs. 71.4%, day 6 vs. day 3, respectively). Beginning support on day 6 also significantly decreased implantation rates in the GnRH agonist group (21.0% vs. 34.0%, day 6 vs. da y 3, respectively). Conclusion(s): Pregnancy rates are significantly decreased by initiating lu teal-phase progesterone supplementation on day 6 after oocyte retrieval dur ing in vitro fertilization cycles. (Fertil Steril (R) 2001;76:1140-3. (C) 2 001 by American Society for Reproductive Medicine.).