Comparison of Crinone 8% intravaginal gel and intramuscular progesterone for luteal support in in vitro fertilization.

381 In their study, Ho et al1 report that using vaginal progesterone gel twice daily for luteal support resulted in better pregnancy outcomes than intramuscular progesterone. Vaginal progesterone gel seemed to offer more “targeted” delivery of progesterone to the uterus and improved endometrial receptivity. The authors also concluded that for patients with serum estradiol levels on the day of human chorionic gonadotropin greater than 5,000 pg/mL, vaginal gel still resulted in better ongoing pregnancy and implantation rates. In vitro fertilization (IVF) is a relatively new field in medicine. Most of the individual studies in luteal phase supplementation in IVF, excluding meta-analyses which have their own limitations, lack adequate power analysis to determine statistical significance, especially if the study is a negative one. Nevertheless, this study addressed the following questions that are still in need of scientific investigation. 1. Should the dose of progesterone be dependent on peak estradiol level, the type of stimulation protocol used, the age or the body weight of the patient? 2. What is the optimal dose of progesterone, both for vaginal gel and intramuscularly administrated preparations (IMP)? 3. Would the protocol benefit from additional estradiol supplementation, what is the optimal dose of estradiol, and when should it start and end? 4. When is the optimal time to start progesterone supplementation? Before embryo transfer? And when should it end? The Importance of Progesterone in Early Pregnancy