Single-Embryo Transfer (SET): Why Clinics Are Moving Away from “Two or More”

In vitro fertilization (IVF) has transformed reproductive medicine, offering hope to people trying to build their families. Historically, transferring multiple embryos during an IVF cycle was common to increase the chances of pregnancy. However, recent advancements and a deeper understanding of associated risks have led fertility specialists to favor single-embryo transfer (SET) over transferring two or more embryos.

What Is Single-Embryo Transfer?

Single-embryo transfer involves implanting only one embryo into the uterus during an IVF cycle. This approach aims to achieve a healthy pregnancy while minimizing the risks associated with multiple gestations.

The Shift Toward Single-Embryo Transfer

The American Society for Reproductive Medicine (ASRM) strongly recommends SET in most IVF cases due to the significant health risks associated with multiple pregnancies. Multiple gestations can lead to complications such as preterm birth, low birth weight, and increased maternal health risks, according to ASRM.

Studies published in Human Reproduction show that the rate of multiple gestations after elective single-embryo transfer (eSET) is approximately 1.6%, with twin pregnancies occurring in 1.56% and triplets in 0.04% of cases. This data underscores the effectiveness of SET in reducing the incidence of multiple pregnancies.

Benefits of Single-Embryo Transfer

• Reduced Risk of Multiple Pregnancies: Significantly decreases the likelihood of twins or higher-order multiples.
• Improved Pregnancy Outcomes: Associated with better perinatal outcomes compared to transferring multiple embryos.
• Lower Maternal Health Risks: Minimizes maternal health risks, including gestational diabetes and preeclampsia.

Considerations for Elective Single-Embryo Transfer

While SET offers numerous advantages, it may not be suitable for every patient. Factors such as maternal age, embryo quality, and previous IVF outcomes can influence the decision. For example, women over the age of 35 or those with a history of unsuccessful IVF cycles may opt for double embryo transfer (DET) to increase their chances of pregnancy.

Decisions about the number of embryos to transfer are made carefully with your fertility specialist to balance the likelihood of pregnancy with safety considerations.

Taking Charge of Your Fertility Journey

Choosing the right IVF approach is an important step in your family-building journey. Single-embryo transfer offers many benefits, but the optimal strategy depends on your individual circumstances, including age, reproductive history, and embryo quality. Open communication with your fertility specialist ensures that your treatment plan balances safety, effectiveness, and your personal goals.

At University Reproductive Associates, we work closely with each patient to create personalized fertility plans that consider the whole picture—including reproductive history, overall health, and family-building goals. If you’re exploring IVF and want guidance on whether single-embryo transfer is right for you, schedule a consultation at URA today.