Rate of blastocyst development from excess embryos remaining in culture after day 3 embryo transfer.

Objective: To assess the rate of blastocyst development (BDR) from embryos remaining in culture after day-3 embryo transfer (ET), and its relationship to cause of infertility.

Study design: Retrospective cohort study in tertiary-care IVF Center. Blastocyst development rate (BDR) after day-3 ET was assessed in 126 women who underwent either conventional IVF or ICSI.

Results: Mean age, early follicular FSH levels, number of 2PN zygotes, number of excess embryos, and number of ET were similar between patients that underwent IVF and ICSI. Overall, 20% of extra embryos from conventional IVF patients developed into blastocysts compared to 14% of embryos obtained from ICSI. Cause of infertility did not affect BDR, even in patients who required ICSI due to male factors.

Conclusions: Low rates of blastocyst development from excess embryos are similar between IVF and ICSI patients. Only 15 to 25% of excess embryos left in culture develop into blastocysts, regardless of cause of infertility. Physicians and patients can use this information to adjust both AR treatment protocols and patient expectations.