Over Ten-Cell Good Embryo Transfers on Day Three have Equivalent Clinical Outcomes with Those of Eight-Cell Embryos in Female Patients Aged ≤35 Years: A Retrospective Cohort Study

Abstract

Background/Aim: To compare the clinical outcomes between > 10- and 8-cell good quality embryos on day 3. Methods: A retrospective study of a cohort of 459 patients was included in the fresh embryo transfer (ET) cycle group from January 2009 to April 2016. In this group, 2 good quality embryos on day 3, were transferred on corresponding dates, in 75 patients (> 10-cell embryos), and in 384 patients (8-cell embryos). Seven hundred and forty four patients, with 1 blastocyst transferred derived from > 10-cell (n = 183) or 8-cell (n = 561) good quality embryos on day 3, were assigned in the frozen ET (FET) group. Results: In the ET group, the clinical pregnancy and live birth rates of the > 10-cell transfer patients were comparable with those of the 8-cell transfer group (62.67 vs. 69.27%, 60.00 vs. 59.90%, respectively); however, the miscarriage rate of > 10-cell transfers was significantly lower than that of 8-cell transfers (4.26 vs. 13.53%, p < 0.05). In the FET group, there were no statistically significant differences found in the clinical pregnancy, live birth, and miscarriage rates between one > 10-cell-derived and one 8-cell-derived blastocyst transfers (71.04 vs. 65.78%, 59.02 vs. 54.19%, and 16.92 vs. 17.62%, respectively). Conclusions: The results suggested that > 10- and 8-cell, good quality embryos on day 3, had comparable viability and clinical outcomes.