Endocrinology: Luteal support after in-vitro fertilization: Crinone 8%, a sustained release vaginal progesterone gel, versus Utrogestan, an oral micronized progesterone

Two progesterone presentations, a vaginal application of 90 mg progesterone per day (Crinone) or 300 mg progesterone administered orally (Utrogestan), were compared for luteal phase support of patients undergoing an in-vitro fertilization (IVF) procedure. A total of 283 patients were randomly allocated to either treatment. The treatment started within 24 h after the embryo transfer procedure and continued until day 30 in cases of implantation. Efficacy was assessed using the pregnancy and delivery rates. Safety was assessed through specific symptoms and usual safety monitoring. The pregnancy rates per transfer were not significantly different in the Crinone and Utrogestan groups at days 12 (Crinone 35.3%, Utrogestan 29.9%, P = 0.55), 30 (Crinone 28.5%, Utrogestan 25.0%, P = 0.61) and 90 (Crinone 25.9%, Utrogestan 22.9%, P = 0.69). No differences in the spontaneous abortion rates were seen thereafter. The delivery rates (number of deliveries per patient; Crinone 23.0%, Utrogestan 22.2%, P = 1.00), as well as the ratio of newborn babies per embryo transferred (Crinone 11.7%, Utrogestan 11.1%, P = 0.91), were not significantly different. Safety parameters were similar in both groups, except for drowsiness, which was more significantly frequent in the oral progesterone group than in the Crinone group at all time points. No serious adverse events were recorded in this study. The fact that Crinone matches the efficacy of the larger doses of progesterone used orally reflects an advantage of the transvaginal route of administration which avoids the metabolic inactivation of progesterone during its first liver pass.