Does supraphysiologic estradiol level during IVF have any effect on oocyte/embryo quality? A sibling embryo cohort analysis of fresh and subsequent frozen embryo transfer.

BACKGROUND

The aim of this paper was to determine the effect of supraphysiologic serum estradiol (E2) level on oocyte and embryo development during IVF cycles.

METHODS

This is a retrospective data analysis of all autologous IVF cycles where fresh embryo transfer was performed followed by subsequent frozen embryo transfer (FET) using cryopreserved sibling embryos. Primary outcome was live birth rate (LBR). Secondary outcomes were oocyte and embryo characteristics.

RESULTS

Patients with high E2 (defined as serum peak E2>50th percentile [3727 pg/mL]) recorded prior to HCG trigger had significantly higher number of matured oocytes, zygotes exhibiting two pronuclei, cleavage stage embryos, blastocysts, and vitrified embryos. Following FET, LBR was higher among patients with high than normal E2 (55% vs. 37%, odds ratio [OR] 2.02; 95% confidence interval [CI] 1.05-3.88, P=0.03). Paired analysis revealed that the likelihood of achieving live birth was higher with FET compared to fresh transfer both among high E2 (54.7% vs. 26.7%; OR 3.3; 95% CI: 1.67-6.58, P<0.001) and normal E2 (37.3% vs. 18.7%; OR 2.6; 95% CI 1.23-5.47, P=0.01) patients.

CONCLUSIONS

Supraphysiologic serum E2 level prior to HCG trigger does not appear to have negative impact on oocyte and embryo quality.