Serum progesterone levels predict success of in vitro fertilization/embryo transfer in patients stimulated with leuprolide acetate and human menopausal gonadotropins

Serum progesterone (P₄) levels greater than 2.86 nmol/L (0.9 ng/mL) on the day of hCG administration are reportedly associated with decreased pregnancy rates in in vitro fertilization/embryo transfer (IVF/ET) cycles. To further assess this phenomenon we measured serial serum P₄, LH, and estradiol levels in 115 consecutive patients undergoing stimulation for IVF/ET with midluteal leuprolide acetate and human menopausal gonadotropins. IVF/ET cycle outcome was retrospectively correlated with P₄ levels on the day of hCG administration. Two critical breakpoints were identified, 1.27 nmol/L (0.4 ng/mL) and 2.86 nmol/L (0.9 ng/mL). Clinical pregnancies occurred in 9 of 18 patients in group I (P₄, <1.27 nmol/L) compared to 11 of 81 patients in group II (1.27 < P₄ < 2.86 nmol/L; P = 0.001) and 0 of 14 patients in group III (P₄, ≤2.86 nmol/L) (P = 0.001). Eleven patients in group III had cryopreservation of embryos during that cycle. Six subsequently underwent frozen embryo transfer, and clinical pregnancies occurred in 2, both of whom have delivered. These findings demonstrate that even modest increases in serum P₄ levels (>1.27 nmol/L) are associated with reduced pregnancy rates in IVF/ET cycles. In addition, it appears that the mechanism may not exclusively involve poor oocyte quality.