Reduced implantation rate associated with a subtle rise in serum progesterone concentration during the follicular phase of cycles stimulated with a combination of a gonadotrophin-releasing hormone agonist and gonadotrophin.

Our objective was to assess the effects of subtle increases in serum progesterone concentration (1.0-2.0 ng/ml) on the outcome of in-vitro fertilization (IVF), particularly on the quality of embryos, during the follicular phase of cycles stimulated with gonadotrophin-releasing hormone agonist (GnRHa) and human menopausal gonadotrophin (HMG). A total of 97 patients underwent 116 cycles of IVF and were stimulated with a combination of HMG and GnRHa. They were divided into two groups: those with a subtle progesterone rise and those with no progesterone rise. The two groups were compared with respect to serum oestradiol, progesterone, immunoreactive luteinizing hormone (I-LH), bioactive LH (B-LH), and results of IVF. The groups did not differ significantly in mean age or in total dose of HMG received. On the day that human chorionic gonadotrophin was administered, concentrations of oestradiol and progesterone were significantly higher in the subtle progesterone rise cycles than in the no progesterone rise cycles. In the no progesterone rise cycles, the percentages for embryos beyond the 4-cell stage, grade 1 embryos, and implantation rates were significantly higher than those in subtle progesterone rise cycles. The combination of GnRHa and HMG eliminated any significant rise in serum I-LH or B-LH concentration during the follicular phase, but did not suppress the subtle rise in progesterone. These results confirm our previous finding that a subtle progesterone rise adversely affects the outcome of IVF. It is also suggested that a reduction in embryo quality may influence the lower rate of implantation in subtle progesterone rise cycles.