More is not always better–lower estradiol to mature oocyte ratio improved IVF outcomes

Abstract

Aim: To find a cut-off ratio of estradiol/metaphase II oocyte (E2/M2) ratio and to evaluate the correlation with patients’ characteristics, embryo morphokinetics using EmbryoScope™ and IVF cycle outcomes. Material and methods: For this retrospective cohort study, records of all fresh cycl es that were cultured and scored by EmbryoScope™ were evaluated. T he peak E2/M2 ratio was calculated on the day of human chorionic gonadotropin (hCG) administration and correlated to embryo morphokinetic quality and cycle outcomes. A receiver operating characteristics analysis was calculated for the E2/M2 ratio and clinical pregnancy rates. Results: A total of 2461 oocytes were collected from 319 patients. Rece iver operating characteristics analysis revealed a cutoff of 204 as a discrimin ative point to predict clinical pregnancy with a sensitivity of 69.5% and specificity o f 62.1% (P 204 group were older, had higher E2 concentration, fewer M2 ooc ytes despite elevated gonadotrophin doses. E2/M2 ratio ≤ 204 was correlated with higher fertilization rate, better embryo quality, higher pregnancy and live birth rates, a nd more frozen embryos. Conclusion: E2/M2 ratio < 204 yielded the best probability to achieve good quality embryos with good morphokinetic scores and better pregnancy outcomes an d may be used to predict IVF cycle outcomes. Advanced maternal age and low ovari an response received higher concentrations of gonadotrophins, which resulted in high er E2/M2 ratio. Milder stimulation to those patients may improve their cycle outcomes.

Keywords

• estradiolmetaphase ii oocyte (e2/m2) ratio
• pregnancy rate
• embryo morphokinetics
• time-lapse incubator