There are better parameters Diagnostics for premature luteinization than isolate value of Progesterone level or progesterone/estradiol ratio on the day of hCG administration?

Abstract

Introduction: Both the absolute value of progesterone (P) and the progesterone/estradiol ratio (P/E) are used for the diag- nosis of early luteinization (EL), without reaching an agreement on the appropriate threshold and with very different results in terms of its predictive ability. The P/E ratio has also created a great deal of confusion between the concept of LP and low ovarian response to hyperstimulation.

The objective of this study is to find a parameter that is independent of the degree of ovarian response and estradiol va- lues.

Methods: We analyzed 434 consecutive IVF cycles with FSH and/or LH stimulation and pituitary down regulation with agonist or antagonists without any prior exclusion criteria to determine the mathematical relationship between progesterone and estradiol at the time prior to ovulation.

Results: The empirical relationship between progesterone and estradiol is established by the formula E=4P2, from which we can deduce the descriptive formulas of P=0,5E0,5, P/E=0,5E-0,5 an P2/E=0,25, being P2/E the only one that corresponds to a constant without dependence on the estradiol level and, therefore, the ideal criterion for the diagnosis of early luteinization.

Conclusion: The progesterone2/estradiol formula is the ideal parameter for diagnosing early luteinization given its independence from the degree of ovarian response to stimu- lation.