There is a cycle to cycle variation in ovarian response and pre-hCG serum progesterone level: an analysis of 244 consecutive IVF cycles

Abstract

We aimed to answer one key question, that was not previously addressed as to whether serum progesterone (P_4-hCG day) and its co-variates (estradiol (E_{2-hCG day}) and the number of retrieved oocytes) of a given cycle can be predictive of the subsequent cycle when both cycles are consecutive and comparable for the stimulation protocol, gonadotropin dose and duration of stimulation. We analyzed such 244 consecutive (< 6 months) IVF cycles in 122 patients with GnRH agonist long protocol and found that P₄, E₂ and the number of retrieved oocytes significantly vary between the two cycles. Although P₄ increased (ranging from 4.7 to 266.7%) in the 2nd cycle in 61 patients, E₂ and the number of retrieved oocytes, which are normally positively correlated with P₄ paradoxically decreased in the 41% and 37.7% respectively, of these same 61 patients. When a similar analysis was done in the 54 out of 122 patients (44.3%) in whom serum P₄ was decreased in the 2nd cycle, the mean decrease in P₄ was - 34.1 ± 23.3% ranging from - 5.26 to - 90.1%. E₂ and the number of retrieved oocytes paradoxically increased in the 42.3% and 40.7% of these 54 patients respectively. P₄ remained the same only in the 7 (5.7%) of these 122 patients. These findings indicate that late follicular phase serum P₄ may change unpredictably in the subsequent IVF cycle. The changes are not always necessarily proportional with ovarian response of previous cycle suggesting that growth characteristics and steroidogenic activities of antral cohorts may exhibit considerable cycle to cycle variations.

Figure 1

The association of P₄ level on the hCG day with E₂ level on the hCG day, and the numbers of fol > 14 mm and retrieved oocytes on the correlation and linear regression analyses in the 1st and 2nd IVF cycles.

Figure 2

Comparison of the means of P₄ on the hCG day (A) and its co-variates E₂ on the hCG day (B), and the numbers of fol > 14 mm on day 10 of stimulation (C) and retrieved oocytes (D) between the 1st and 2nd IVF cycles are shown as scatter plot with bars (the left images graphics). The variations in these parameters between the cycles are also shown as lines (the right graphics).

Figure 3

Scatter plot diagrams of the percent changes of P₄ on the hCG day and its correlates E₂ on the hCG day, and the numbers of fol > 14 mm on day 10 of stimulation and retrieved oocytes overall (A), and when P₄ in the second cycle is > 0 (B), < 0 (C) or = 0 (D). Paradoxical changes in the co-variates of P₄ (Y-axis) when P₄ increased and decreased are visible on the X-axis.

Figure 4

Histogram depiction of the percent change of P₄ in the 2nd cycle (x-axis) and the corresponding percent change in E₂, and the numbers of fol > 14 mm and retrieved oocytes (y-axis). Light green areas show the cycles in which there are parallel changes in P₄ and its co-variates (E₂ and the numbers of fol > 14 mm and retrieved oocytes). Light blue areas demonstrate the cycles in which there were paradoxical changes in P₄ and its correlates. Solid line: linear regression, dotted line 95% confidence intervals.