High implantation and pregnancy rates with transfer of human blastocysts developed in preimplantation stage one and blastocyst media

Objective: To evaluate the proficiency of preimplantation stage one (P1) and blastocyst media in supporting human blastocyst development and to document implantation and clinical pregnancy rates from the transfer of the normally developed blastocysts. Design: Retrospective clinical study. Setting: Private IVF unit of a university-affiliate center. Patient(s): Twenty-eight women aged 33.7 +/- 2.9 years who underwent IVF treatment for infertility. Intervention(s): Bipronucleate oocytes obtained from IVF and intracytoplasmic sperm injection were cultured in vitro with P1 and blastocyst media for 96-120 hours. One to three embryos were transferred (2.1 +/- 0.2 for the patients who became pregnant and 1.5 +/- 0.3 for those who did not become pregnant). Main Outcome Measure(s): Total number and percentage of developed blastocysts, frequency of blastocysts of grades A and B, and implantation and pregnancy rates. Result(s): From 431 oocytes retrieved, 269 bipronucleate oocytes were cultured, producing 81 blastocysts that resulted in the transfer of 54 embryos in 27 procedures. Blastocysts developed in 39.7% +/- 5.5% of the pregnant group and 30.2% +/- 4.5% of the nonpregnant group. From 15 (15/27 = 55.6%) clinical pregnancies, 18 (18/54 = 33.3%) gestational sacs were visualized. The rate of implantation in the pregnant group was 58.1% (18/31). Conclusion(s): These results provide evidence for the benefits of extending human embryo culture with P1 and blastocyst media for all normally fertilized embryos in vitro. (Fertil Steril(R) 1998;70:659-63. (C) 1998 by American Society for Reproductive Medicine.).