Casting for determinants of blastocyst yield and of rates of implantation and of pregnancy after blastocyst transfers

Objective To identify determinants of blastocyst yield, implantation rate, and pregnancy outcome. Design Retrospective analysis of outcomes of 1,653 cycles of IVF. Setting Private infertility clinic. Patient(s) Couples presenting to an infertility clinic for IVF. Intervention(s) None. Main Outcome Measure(s) Blastocyst yield, implantation rate, and pregnancy. Result(s) Of a broad array of potential determinants, only the total numbers of oocytes retrieved and properties of day 3 embryos were consistently predictive of blastocyst formation. Relative to numbers of oocytes fertilized by intracytoplasmic sperm injection (ICSI), yields of quality blastocysts were highest in cycles in which