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Blastocyst score affects implantation and pregnancy outcome: towards a single blastocyst transfer
D K Gardner1, M Lane, J Stevens
1Colorado Center for Reproductive Medicine, Englewood, Colorado, USA. dgardner@colocrm.com
Objective:
To determine the relationship between blastocyst score and pregnancy outcome.
Design:
Retrospective review of blastocyst transfer in an IVF clinic.
Setting:
Private assisted reproductive technology unit.
Patient(S):
107 patients undergoing blastocyst culture and transfer of two embryos.
Intervention(S):
Culture of all pronucleate embryos in sequential media to the blastocyst stage (day 5), followed by transfer of two blastocysts.
Main Outcome Measure(S):
Implantation rates, pregnancy rates, and twinning were analyzed.
Result(S):
When a patient received two top-scoring blastocysts (64% of patients), implantation and pregnancy rates were 70% and 87%, respectively. The twinning rate in this group was 61%. When only one top-quality blastocyst was available for transfer (21% of patients), the implantation and pregnancy rates were 50% and 70%. The twinning rate for this group was 50%. In contrast, when only low-scoring blastocysts were available for transfer (15% of patients), implantation and pregnancy rates were 28% and 44%, and the twinning rate was 29%. No monozygotic twins were observed in this group of patients.
Conclusion(S):
The ability to transfer one high-scoring blastocyst should lead to pregnancy rates greater than 60%, without the complication of twins.
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