Oral versus intramuscular progesterone for in vitro fertilization: a prospective randomized study

OBJECTIVE: To evaluate the efficacy of oral micronized progesterone compared with IM progesterone in oil for luteal support in patients undergoing IVF who are treated with a GnRH agonist. DESIGN: Randomized prospective clinical trial. SETTING: University-based IVF center. PATIENT(S): Women <40 years of age who were undergoing IVF with luteal GnRH pituitary down-regulation. INTERVENTION(S): Patients were randomized to receive either oral micronized progesterone (200 mg three times daily) or IM progesterone (50 mg daily). MAIN OUTCOME MEASURE(S): Progesterone levels at standardized days 21 and 28, and pregnancy and embryo implantation rates. RESULT(S): Day 21 progesterone levels were 77.6+/-13.2 ng/mL in the IM group and 81.5+/-16.2 ng/mL in the oral group. Day 28 progesterone levels were 76.3+/-15.0 ng/mL in the IM group and 53.6+/-10.1 ng/mL in the oral group. The clinical pregnancy rates were 57.9% and 45.8% for the IM and oral groups, respectively. The implantation rate per embryo was significantly higher in the IM group (40.9%) than in the oral group (18.1%). CONCLUSION(S): When used according to our protocols, oral progesterone and IM progesterone result in comparable levels of circulating progesterone. However, oral progesterone results in a reduced implantation rate per embryo.