Sibling embryo blastocyst development correlates with the in vitro fertilization day 3 embryo transfer pregnancy rate in patients under age 40.

OBJECTIVE: To examine the IVF day 3-ET pregnancy rate in patients under 40 with sibling embryo blastocyst development, compared with similar patients without blastocyst formation.
DESIGN: Retrospective analysis.
SETTING: Academic infertility center. PATIENT(S): One hundred twenty-five IVF day 3-ET patients under 40 with sibling embryos for extended culture. INTERVENTION(S): Extended culture of nontransferred sibling embryos for blastocyst development. MAIN OUTCOME MEASURE(S): Pregnancy and multiple gestation rates, number of oocytes, embryos formed, and embryos transferred. RESULT(S): Thirty-eight percent of patients became pregnant. Forty-eight percent of patients had sibling embryos develop to blastocyst. The blastocyst group had more oocytes retrieved (17.4+/-6.6 versus 14.4+/-5.6), more embryos formed (11.2+/-4.2 versus 8.8+/-3.2), and a higher clinical pregnancy rate (60% versus 18%) than the group without blastocyst development. CONCLUSION(S): Blastocyst transfer has been shown to improve implantation rates and reduce the risk of multiple gestations from assisted reproductive technology. Sibling embryo blastocyst development may reflect superior embryo quality, as manifested by increased IVF-ET pregnancy rates. In addition to predicting pregnancy in the current cycle, sibling embryo blastocyst development may provide information about the potential for fresh blastocyst transfer in subsequent cycles and help to identify patients at risk for multiple gestations.