Laser-assisted removal of necrotic blastomeres from cryopreserved embryos that were partially damaged

Rienzi, Laura; Nagy, Zsolt Peter; Ubaldi, Filippo; Iacobelli, Marcello; Anniballo, Reno; Tesarik, Jan; Greco, Ermanno

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Volume 77, Issue 6 , Pages 1196-1201, June 2002

Laser-assisted removal of necrotic blastomeres from cryopreserved embryos that were partially damaged

Presented in part at the 55th Annual Meeting of the American Society for Reproductive Medicine, Toronto, Ontario, Canada, September 25–30, 1999.

Laura Rienzi, B.Sc.
- Reprint requests: Laura Rienzi, B.Sc., Centre for Reproductive Medicine, European Hospital, Via Portuense 700, 00149 Rome, Italy (FAX: 39-06-65975727)
- Centre for Reproductive Medicine, European Hospital, Rome, Italy
Zsolt Peter Nagy, M.D., Ph.D.
- Clinica de Reproducão Humana, São Paulo, Brazil
Filippo Ubaldi, M.D.
- Centre for Reproductive Medicine, European Hospital, Rome, Italy
Marcello Iacobelli, B.Sc.
- Centre for Reproductive Medicine, European Hospital, Rome, Italy
Reno Anniballo, M.D.
- Andrology Centre John MacLeod, Naples, Italy
Jan Tesarik, M.D.
- MAR&Gen, Molecular Assisted Reproduction and Genetics, Granada, Spain
Ermanno Greco, M.D.
- Centre for Reproductive Medicine, European Hospital, Rome, Italy

Received 24 July 2001; received in revised form 21 February 2002; accepted 21 February 2002.

Abstract

Objective: To examine whether the developmental potential of embryos that were partially damaged after freezing and thawing can be improved by removal of necrotic blastomeres before embryo transfer.

Design: Prospective pilot study and observational clinical series.

Setting: Private hospital.

Patient(s): Two hundred thirty-five infertile couples undergoing frozen embryo transfer.

Intervention(s): Removal of necrotic blastomeres from frozen-thawed human embryos.

Main Outcome Measure(s): Pregnancy and implantation rates.

Result(s): Removal of necrotic blastomeres from partially damaged frozen-thawed embryos before transfer increased rates of pregnancy (45.7% vs. 17.1%), ongoing pregnancy (40.0% vs. 11.4%) and ongoing implantation (16.2% vs. 4.3%) compared with the control group, in which necrotic blastomeres were not removed. A similarly high implantation rate (16.7%) was seen a subsequent clinical series in which necrotic blastomeres were removed from all partially damaged embryos.

Conclusion(s): The viability of partially damaged frozen-thawed embryos can be improved by removal of necrotic blastomeres before embryo transfer.

Keywords: Cryopreservation, embryos, human, laser-assisted hatching, necrotic blastomere removal