Is it acceptable to destroy or include human embryos before day 5 in research programmes?

Area of Science:

• Reproductive Medicine
• Embryology
• Genetics

Background:

• Day-3 poor-quality embryos (PQE) from IVF are typically discarded or used for research.
• PQE possess the potential for blastocyst development and embryonic stem cell line derivation.

Purpose of the Study:

• To investigate the developmental potential of PQE beyond day 3 of in vitro culture.
• To assess the viability and implantation potential of blastocysts derived from PQE.
• To evaluate the live birth rate following the transfer of thawed blastocysts derived from PQE.

Main Methods:

• A prospective study involving 186 IVF candidates with supernumerary PQE.
• Extended culture of PQE to assess blastocyst development.
• Cryopreservation of high-quality blastocysts derived from PQE.
• Thawed blastocyst transfer cycles followed by pregnancy monitoring.

Main Results:

• Out of 620 eligible PQE, 217 (35.0%) reached the blastocyst stage, with 73 (33.6%) cryopreserved.
• Blastulation rates were significantly higher (OR 7.29) for embryos compacted on day 4.
• Thirty-three thawed blastocyst transfer cycles resulted in 10 clinical pregnancies, yielding five healthy live births.

Conclusions:

• Poor-quality embryos can develop to the blastocyst stage and, after cryopreservation and thawing, demonstrate reasonable implantation potential.
• The findings suggest that PQE may be a viable source for achieving live births, warranting a re-evaluation of their ethical disposition.