Serum progesterone concentration on day of HCG administration and IVF outcome

To determine the relationship between serum progesterone on the day of human chorionic gonadotrophin (HCG) and the pregnancy outcome of IVF–embryo transfer treatment, 251 infertile patients undergoing IVF–embryo transfer with gonadotrophin-releasing hormone agonist (GnRHa) and recombinant FSH (rFSH) were prospectively studied. Among them, 118 patients underwent 118 cycles of frozen embryo transfer (FET) treatment, one cycle per patient. All the cycles were grouped according to serum progesterone concentration on the day of HCG administration (<3.97 nmol/l or ≥3.97 nmol/l). The incidence of progesterone elevation was 36.7% (92/251), and in this group the pregnancy rate was significantly lower (25.97 versus 48.57%; P < 0.001). If the serum progesterone on the day of HCG was over 6.0 nmol/l, their pregnancy outcome was much poorer (13.79 versus 44.68%). However, the pregnancy rate was similar in FET cycles whether the serum progesterone was over 3.97 nmol/l (34.00 versus 36.76%) or 6.0 nmol/l (42.86 versus 34.02%). In conclusion, serum progesterone on the day of HCG may predict IVF pregnancy outcome. The higher serum oestradiol and progesterone concentrations may affect endometrial receptivity. For patients with an extremely high progesterone concentration on the day of HCG (such as over 6.0 nmol/l), transfer of frozen embryos in a natural cycle is suggested.