The integrated luteal progesterone: an assessment of luteal function

An integrated luteal progesterone (ILPL) was calculated on the basis of a luteal progesterone (P) level with the assumption that the daily plasma P level in the luteal phase closely approximates a sine curve. The midluteal P-amplitude (K) was also obtained mathematically. Daily luteal P levels from five normal ovulatory cycles were assessed for the biologic variation of ILPL and K, then compiled to construct a normogram of the ILP during the luteal phase. The coefficient of variation of K and total ILPL in each cycle ranged from 9.7% to 24.3% and 3.5% to 13.2%, respectively. Fifty-two infertility patients were evaluated for their luteal function by the luteal P and estradiol (E2) level, K, ILPL, endometrial biopsy (EBX)-lag-day, as well as the lengths of follicular phase, luteal phase (L#), and cycle. Thirty-nine patients had EBX-lag day less than or equal to 2 days and were designated as infertile-normal (INF-NL) luteal phase, while the remaining 13 patients who had EBX-lag day greater than 2 days were considered as luteal phase defect (LPD). Significant (P less than 0.05) differences were observed between INF-NL and LPD in: luteal length (13.2 +/- 0.31 versus 11.0 +/- 0.58 days, respectively), and total ILPL (170 +/- 8.3 versus 113 +/- 8.5 ng/ml-day, respectively). No differences were seen in luteal P, E2 and K levels, nor in follicular and cycle length. Significant (P less than 0.05) correlations were observed between total ILPL and luteal P, E2, L#, and K; while a negative correlation was noted between follicular and luteal length.(ABSTRACT TRUNCATED AT 250 WORDS)