Purpose: This study aimed to determine whether the presence of an uncleaved embryo on day 3 is predictive of cycle outcome after day 5 transfer (D5 ET).
Methods: In vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) cycles from January 2013 to November 2014 with D5 ET were analyzed for the presence of at least one uncleaved embryo on day 3 (D3). Each index cycle (n = 70) was compared with two matched control cycles without uncleaved embryos. The main outcome measures included embryo quality, implantation rate, and clinical pregnancy rate.
Results: Fifty-nine of 3896 total embryos in this study were uncleaved on D3 (1.5 %). Cycles with uncleaved embryos had more oocytes retrieved (20.6 vs. 17.5), lower proportions of good quality embryos on D3 (52.4 vs. 66.1 %), and fewer usable embryos (transferred or frozen) on D5 (42.4 vs. 50.8 %). However, there were no significant differences in the incidence of cycles with a positive hCG, or in the rates of implantation, clinical pregnancy, or live birth.
Conclusions: Although an uncleaved embryo on D3 is associated with reduced conversion of sibling embryos to the blastocyst stage on D5, overall quality of those embryos forming blastocysts is not markedly decreased and clinical outcomes are not compromised.
Keywords: Day 5 transfer; IVF; Uncleaved embryo.