The preovulatory serum estradiol pattern in natural IVF/ICSI cycles

The aim of the study was to find whether inferences to the possible success of natural IVF/ICSI cycles could be drawn from the estradiol (E2) pattern.

Sixty-eight women who underwent oocyte recovery in 98 natural cycles were recruited for the study. Daily serum E2 was measured in the preovulatory phase (-3 to +2 day). The E2 pattern was compared among four groups: Group A, unsuccessful egg retrieval; Group B, no fertilization; Group C, no implantation; and Group D, implantation.

There was no difference in mean E2 levels between groups. Only the ratio of E2 on day +1/E2 on day 0 was significantly lower in conception cycles in comparison with nonconception cycles. In cycles with a decreased E2 level on day +1, only the implantation rate was significantly higher in comparison with cycles with an increasing E2 level.

From the E2 pattern it is possible to make inferences about the likelihood of implantation but not the fertilization or oocyte recovery success.