Single Embryo Transfer (SET) vs Double Embryo Transfer (DET)

A question that often comes up in assisted reproductive technology is, “How many embryos should we transfer?” Because the health and safety of everyone is a priority, our agency only works with Intended Parents and Gestational Carriers who are willing to undergo a single embryo transfer.

What exactly is the difference between a DET (double embryo transfer) and SET (single embryo transfer)? When undergoing a SET, only one embryo is transferred to a woman’s uterine lining. A DET involves two embryos being transferred. The goal of ART (assisted reproductive technology) is to produce a healthy singleton pregnancy. The safest way to reach this goal is through SET. Singleton pregnancies have lower risks for both the carrier and baby.

Double embryo transfers are more likely to result in multiple pregnancies. Multiple pregnancies carry many risks and complications for both the carrier and babies.

Potential risks and complication include:  

·        Prolonged bed rest

·        High blood pressure

·        Premature birth- almost 3 out of 5 twin babies are born prematurely

·        Cesarean delivery

·        Low birth Weight

·        NICU care for babies- twin babies are more than five times as likely to be admitted to the NICU compared to single babies

DET is not as common of a practice as it was in the past. As ART practices are improving, the occurrence of DET is decreasing significantly. This is because of the implications associated with transferring more than one embryo at a time. According to the American Society for Reproductive Medicine (ASRM), data from 2000 to 2017 shows the proportion of SET has increased from 5.7 to 64.2%, among ART-conceived infants, meanwhile the percentage of multiple births has decreased from 53.1 to 26.4%. Concurrently with a decrease in DET, data indicates a steady decrease in preterm birth and low birth weight rates.  

If DET carries greater risk to both baby and carrier, why pursue it? Motivation for DET is often financial in nature. IPs only have a set number of embryos. If the first embryo transfer is unsuccessful, IPs must finance a second transfer. It is important to remember, DET do not increase the odds of a successful transfer, but they do increase the likelihood of a multiple pregnancy.

Our goal is to help parents achieve their dreams of parenthood. The safest way to do this is by following ASRM and CDC guidelines and best practices- supporting SET procedures. 

For more information, please take a moment to read what the CDC and ASRM have to say with regard to SET vs DET. 

Informational Links

CDC Having Healthy Babies One at a Time

Guidance on the limits to the number of embryos to transfer: a committee opinion

Multiple Pregnancy Is Risky | ASRM

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