This study was designed to compare the effectiveness of intramuscular progesterone with that of intravenous albumin in the prevention of ovarian hyperstimulation syndrome (OHSS). Ninety-six patients at high risk to develop OHSS (estradiol concentration 19,000 pmol/l on the day of hCG administration and over 20 follicles of a diameter larger than 14 mm observed by transvaginal ultrasonography) and undergoing in vitro fertilizationembryo transfer were enrolled. They were randomly treated with intramuscular progesterone (200 mg/day) or 100 ml of 20% intravenous albumin in order to estimate the difference in the incidence of OHSS. A significant difference in the incidence of moderate OHSS and no cases of severe OHSS were observed between the groups. Our data show the effectiveness in preventing OHSS with high doses of progesterone.
