Serum progesterone concentrations on the day of HCG administration cannot predict pregnancy in assisted reproduction cycles.

The effect of subtle rises of progesterone in the late follicular phase of cycles of ovarian stimulation with gonadotrophin-releasing hormone (GnRH) agonists on pregnancy outcome is controversial. This study used receiver-operating characteristic (ROC) analysis to gain further insight into the predictive value of serum progesterone concentrations on the day of human chorionic gonadotrophin (HCG) injection in normally responding patients receiving the long protocol of GnRH agonist (group L; n = 218) and in low responders receiving the short ('flare-up') protocol (group S; n = 159). ROC analysis showed that serum progesterone concentration on the HCG day was not indicative of conception and non-conception cycles in the whole population studied, in group L or in group S. To further assess the potential impact of 'high' concentrations of circulating progesterone on the day of HCG administration on pregnancy rates and outcome, the threshold value (<0.9 ng/ml) to discriminate between women with 'high' (group H; n = 197) and 'normal' (group N; n = 180) progesterone was applied. No significant differences were found with respect to pregnancy and miscarriage rates between these two groups. Serum progesterone concentrations on the day of HCG administration therefore cannot predict pregnancy in assisted reproduction cycles using GnRH agonists and gonadotrophins.