Normal Embryo Transfer Procedure for IVF
The current standard of care for embryo transfer in IVF is elective single embryo transfer (eSET), which should be practiced regardless of patient age, previous failed cycles, duration of infertility, or embryo quality, as this approach maintains equivalent cumulative live birth rates while dramatically reducing multiple pregnancy complications. 1
Number of Embryos to Transfer
Single Embryo Transfer as Standard Practice
eSET should be the default approach for all IVF patients, as the cumulative live birth rate after repeated SET cycles is equivalent to a single cycle of double embryo transfer (DET), while avoiding the 30-fold increased risk of multiple pregnancy 2
The decision to perform DET instead of eSET should not be based on:
Specific Populations Requiring Mandatory eSET
- Donated embryo transfers: Only eSET should be practiced with no exceptions 1, 2
- Gestational carriers: Only eSET should be practiced 1
- Vitrified-warmed blastocyst transfers: SET should be applied regardless of blastocyst quality 1, 3
When More Than One Embryo May Be Considered
Transfer of more than two embryos is never recommended due to the high risks of higher-order multiple pregnancies 1
In exceptional circumstances where DET might be discussed (though not recommended), this should be limited to:
Embryo Stage and Timing
Cleavage Stage vs Blastocyst Transfer
Fewer blastocyst stage embryos should be transferred compared to cleavage stage embryos due to higher implantation rates, particularly in women with excellent prognoses and high-quality blastocysts 4
Day 2 versus day 3 embryo transfer timing does not significantly affect pregnancy outcomes when the same number of embryos are transferred 5
Frozen Embryo Transfer Considerations
One embryo should be cryopreserved per device to facilitate SET practice and ensure traceability 1
In cryopreserved-warmed cleavage-stage embryo transfer cycles, the decision to perform DET instead of SET should not be based on embryo criteria 1
Critical Risks of Multiple Embryo Transfer
Maternal Complications
- DET is associated with significantly elevated risks of:
Neonatal Complications
Multiple pregnancy rate is 30-fold higher with DET compared to repeated SET (OR 30.54,95% CI 7.46-124.95) 2
Even singleton pregnancies after DET carry higher risks of neonatal death and complications compared to SET 2
Risk of ectopic pregnancy increases up to 20-fold with the number of embryos transferred 2
Risk of monozygotic twinning is higher with blastocyst transfer, creating twin risk even with SET 2
Patient Counseling Requirements
Mandatory Discussion Points
Healthcare professionals must discuss with patients: 1
- Medical, economic, social, and psychological consequences of transferring more than one embryo
- Patient wishes regarding family building
- Clinical, science-based recommendations for the specific patient case
Key Counseling Messages
Cumulative live birth rates with repeated SET are equivalent to DET while avoiding twin risks 2
Patients should be advised against assuming previous pregnancy loss indicates a need for DET 2
Fetal reduction should never be planned as a backup strategy—the transfer of two or more embryos with the intention of performing fetal reduction is not recommended 1
Common Pitfalls to Avoid
Do not increase embryo number based on patient pressure or anxiety about success rates—the evidence clearly shows equivalent cumulative outcomes with SET 2
Do not use patient age alone as justification for multiple embryo transfer—even in older women, the risks of multiple pregnancy outweigh potential benefits 1, 4
Do not assume that "better quality" embryos justify DET—embryo quality should not determine the decision between SET and DET 1