Two-blastocyst transfer has similar pregnancy rates and a decreased multiple gestation rate compared with three-blastocyst transfer.

OBJECTIVE To examine the effect of the number of blastocysts transferred on pregnancy and multiple gestation rates. DESIGN Retrospective study. SETTING Academic infertility center. PATIENT(S) Patients < 40 years undergoing IVF, with FSH levels of < 15 mIU/mL and more than three eight-cell embryos. INTERVENTION(S) Embryos were cultured in P1 until day 3 and then transferred to blastocyst medium. A maximum of three blastocysts were transferred. MAIN OUTCOME MEASURE(S) Pregnancy, multiple gestation, and implantation rates. RESULT(S) All 55 patients developed blastocysts and underwent ET. Twenty-four patients had three embryos transferred and 29 patients had two embryos transferred. Two patients had only one embryo each for transfer. There was no difference in the viable pregnancy rate between the two-blastocyst transfer and three-blastocyst transfer groups (62% vs. 58%). In the two-blastocyst transfer group, 39% of pregnancies were multiple gestations (all twin gestations), compared with 79% of pregnancies in the three-blastocyst transfer group (50% twin gestations, 29% triplet gestations). The implantation rate was 47% in both groups. CONCLUSION(S) A commercially available, sequential culture system is highly effective for producing viable blastocysts. Two-blastocyst transfer eliminated the risk of triplets while maintaining the same high success rates seen with three-blastocyst ET.

[1]  J. Czyba,et al.  Improvement of human early embryo development in vitro by coculture on monolayers of Vero cells. , 1989, Biology of reproduction.

[2]  D. Gardner,et al.  Culture and transfer of human blastocysts increases implantation rates and reduces the need for multiple embryo transfers. , 1998, Fertility and sterility.

[3]  T. Pool,et al.  Preliminary clinical experience with human blastocyst development in vitro without co-culture. , 1999, Human reproduction.

[4]  M. Tsirigotis.  Blastocyst stage transfer: pitfalls and benefits. Too soon to abandon current practice? , 1998, Human reproduction.

[5]  G. Zeilmaker,et al.  A prospective, randomized study of embryo transfer results after 3 or 5 days of embryo culture in in vitro fertilization. , 1996, Fertility and sterility.

[6]  A. Templeton,et al.  REDUCING THE RISK OF MULTIPLE BIRTHS BY TRANSFER OF TWO EMBRYOS AFTER IN VITRO FERTILIZATION , 1999 .

[7]  D. Gardner,et al.  A prospective randomized trial of blastocyst culture and transfer in in-vitro fertilization. , 1998, Human reproduction.

[8]  E. Baracat,et al.  High implantation and pregnancy rates with transfer of human blastocysts developed in preimplantation stage one and blastocyst media. , 1998, Fertility and sterility.

[9]  J. van Blerkom,et al.  ATP content of human oocytes and developmental potential and outcome after in-vitro fertilization and embryo transfer. , 1995, Human reproduction.

[10]  V. Bolton,et al.  Pregnancies after in vitro fertilization and transfer of human blastocysts. , 1991, Fertility and sterility.

[11]  B. Behr,et al.  Sibling embryo blastocyst development correlates with the in vitro fertilization day 3 embryo transfer pregnancy rate in patients under age 40. , 1999, Fertility and sterility.