The role of single-embryo transfer and shifting practice patterns in reducing multiple-birth–related defects
In recent years, fertility medicine has evolved toward prioritizing single-embryo transfer (SET) instead of the older practice of transferring two or more embryos at once. According to studies published in Human Reproduction (2025) and guidelines from ASRM (American Society for Reproductive Medicine) and ESHRE (European Society of Human Reproduction and Embryology), this shift has significantly reduced multiple gestation pregnancies (twins, triplets) without compromising the overall live birth rate.
What’s Changing
- Previously, clinics transferred multiple embryos to increase pregnancy chances, but this often resulted in twin or triplet births—a major risk factor for premature delivery, low birth weight, and congenital abnormalities.
- Now, with improved embryo selection, blastocyst culture, and genetic screening (PGT-A), SET offers high success rates comparable to multi-embryo transfers while drastically reducing birth complications.
Health Impact
- Multiple-birth–related defects like cerebral palsy, congenital heart disease, and respiratory issues are much less frequent with SET.
- Maternal health outcomes—such as reduced preeclampsia, gestational diabetes, and C-section risk—are also improved.
- Recent SART (2025) data show that eSET (elective single embryo transfer) cuts the rate of multiple births by over 50%, with no reduction in healthy live births.
Global Trend
- ESHRE 2024 guidelines recommend SET for women under 38 and for all cases with high-quality embryos.
- Digital embryo scoring AI and time-lapse imaging are enabling better embryo selection, supporting this safer practice.
Key Takeaway
Shifting from quantity to quality—transferring one strong embryo rather than multiple—is one of the most successful safety transformations in IVF/ART, protecting both mother and child from avoidable defects.