“Should we transfer one embryo or two?” is one of the most common questions before embryo transfer day. Many people assume more is better — but the evidence tells a more nuanced story.
The Two Options
SET (Single Embryo Transfer) — one embryo transferred DET (Double Embryo Transfer) — two embryos transferred
Direct Comparison
| SET | DET | |
|---|---|---|
| Pregnancy rate per cycle | Slightly lower | Slightly higher |
| Twin pregnancy risk | Very low | Significantly higher |
| Preterm birth risk | Lower | Higher |
| Best suited for | Good quality embryo, younger patient | Moderate quality, previous failures |
| Current standard | ✅ Recommended as default | Specific cases only |
Why SET Is Now the Recommended Standard
1. Twin pregnancy carries more risk than most people realize
A twin pregnancy from ICSI is not simply a “bonus” outcome. It carries significantly higher risks including:
- Preterm birth
- Low birth weight
- Gestational hypertension
- Higher likelihood of caesarean delivery
- NICU admission for newborns
2. Cumulative success rates are comparable
When you factor in subsequent FET cycles using frozen embryos, the overall probability of having a baby across all cycles is similar for SET and DET — but SET is considerably safer.
3. PGT-A makes SET more effective
With PGT-A, only chromosomally normal embryos are transferred. The implantation rate per transfer rises substantially, making it unnecessary to transfer two embryos to improve odds.
When DET Might Be Considered
Despite SET being the standard, there are specific cases where DET may be discussed:
- Older patients with moderate embryo quality
- Multiple unexplained failed cycles
- No PGT-A performed and uncertain embryo quality
This is always an individual discussion with your treating doctor.
FAQ
Is the success rate much lower with SET?
Per cycle, it may be slightly lower. But cumulative success across all cycles (including frozen transfers) is comparable — and SET is significantly safer.
We’d like twins — can we request two embryos?
Your doctor will discuss this based on your specific situation. It’s important to understand that twin pregnancies carry meaningful medical risks for both mother and babies.
If SET doesn’t work, do I have embryos left for another try?
If you have frozen embryos remaining, yes — FET in a subsequent cycle is an option. Your doctor will discuss this during treatment planning.
Does PGT-A make SET more viable?
Yes. PGT-A selects chromosomally normal embryos, which have significantly higher implantation rates — making SET effective enough that the incremental benefit of DET is reduced
Who makes the final decision on how many embryos to transfer?
Your doctor will make a recommendation based on your situation, but the decision is ultimately yours. All options and their trade-offs will be explained clearly before transfer day.
Where can I discuss embryo transfer options at GFC?
Line @gfcclinic or call 097-484-5335.
Summary
Current international guidelines recommend SET (single embryo transfer) as the default — particularly when PGT-A is used. Cumulative success rates are comparable to DET, while the risks associated with twin pregnancy are avoided.
→ Learn about PGT-A → PGT-A Explained → ICSI at GFC → ICSI Treatment → Book a Free Consultation or Line @gfcclinic | Tel: 097-484-5335
