Comparison of two progesterone dose regimens for luteal phase support after embryo transfer: a prospective randomized study.

Aim: Luteal phase support has been demonstrated as being necessary in patients undergoing IVF/ET after pituitary desensitization with a gonadotrophin releasing hormone agonist (GnRHa). Routine luteal phase supports with progesterone (P) or human chorionic gonadotrophin (HCG) have been proposed. As HCG was shown to lead to a higher incidence of severe ovarian hyperstimulation syndrome (OHSS), supplementation of the luteal phase with P was preferred. The objectives of this study were to compare the absorption and the efficacy (implantation and pregnancy rates) of two different dose regimens of P administered vaginally. Material and methods: Ovarian stimulation was performed with highly purified FSH (Metrodin HP, Serono, Switzerland) after down regulation (Decapeptyl 0.1 mg, Ferring, Switzerland) using a long protocol. The ovulation was induced with 10'000 IU HCG (Profasi, Serono). Forty patients undergoing IVF-ET were prospectively randomized in two groups (n = 20), depending on the dose of vaginal P (Utrogestan, Laboratoire Golaz, Switzerland) administered: Group 1: 2 times 200 mg per day, Group 2: 2 times 300 mg per day. The main outcome measures were (1) serum estradiol (E2) and P levels during the luteal phase (2, 6, 10 and 14 days after ET); (2) implantation and pregnancy rates (serum HCG and cardiac activity observed respectively 14 and 28 days after ET). Statistical analysis were performed using the unpaired two-tail Student's t-test or contingency tables. Results and conclusions: An equal number of four pregnancies (25% per embryo transfer) and a similar implantation rate (18%) were obtained in each group of patients. Among the non pregnant patients, the decrease of serum P levels during the luteal phase was similar in the two groups, independently of the P dose administered. The serum P levels stabilized ten days after transfer at a level of 30-40 nmol/l which is compatible with the occurrence of a pregnancy. A significant increase of P was observed in seven of the eight pregnant patients between day 6 and 10 after embryo transfer corresponding to the period of implantation. This increase was always positively correlated with the confirmed diagnosis of pregnancy on day 14. In conclusion, a dose of 2 times 200 mg P per day administered vaginally constitutes a sufficient luteal phase support after IVF-ET in down regulated cycles.