Ovarian stimulation for assisted reproduction with HMG and concomitant midcycle administration of the GnRH antagonist Cetrorelix according to the multiple dose protocol: a prospective uncontrolled phase III study

A total of 346 women with normal ovulatory function was stimulated with human menopausal gonadotrophins (HMG) to attain ovarian stimulation for IVF or intracytoplasmic sperm injection (ICSI). Stimulation with HMG started on cycle day 2 or 3. After 6 days of stimulation, Cetrorelix in its minimum effective multiple dose of 0.25 mg/day, was administered daily until induction of ovulation. In total, 333 patients (96.2%) reached the day of HCG administration, and 324 (93.6%) underwent oocyte retrieval. A mean of 25.2 ampoules of HMG was applied for a mean of 10.4 days. Cetrorelix was administered for a mean time lapse of 5.7 days. The mean normal fertilization rate was 60% in the IVF group and 59% in the ICSI group. Seventy pregnancies were attained, reflecting an ongoing clinical pregnancy rate of 24% per transfer. The ongoing clinical implantation rate was 11.4%. Only three cases of raised luteinizing hormone (LH) (≥10 IU/I) with increased progesterone secretion (≥1 ng/ml) were observed after initiation of Cetrorelix administration, reflecting an incidence of premature luteinization of 0.9%. The abortion rate was 17%. The incidence of severe ovarian hyperstimulation syndrome (World Health Organization grade III) was as low as 0.6%.