Comprehensive assessment of serum estradiol impact on selected physiologic markers observed during in-vitro fertilization and embryo transfer cycles

OBJECTIVE: This investigation assessed the effect of serum estradiol levels on outcomes of in-vitro fertilization and embryo transfer (IVF) cycles. MATERIALS AND METHOD: This was a retrospective cohort study of 1123 IVF cycles comparing impact of estradiol (E(2)) levels on follicular development, fertilization, embryo quality, implantation, pregnancy rate, miscarriage rate, and selected obstetric complications. RESULTS: We found high serum E(2) levels to be significantly associated with increased number of mature follicles and mature oocytes retrieved (p<0.01, for both). E(2) levels were also associated with more viable and good-quality embryos (p<0.01). There was no significant impact of E(2) on oocyte maturation, fertilization rate, embryo quality, or overall pregnancy rates. Moreover, high E(2) levels were significantly associated with higher implantation rates and reduced incidence of miscarriage (p<0.05, for both). CONCLUSION: Within the safety range in clinical practice, our data demonstrate a generally positive effect of high serum E(2) on selected IVF parameters.