Key points on elective single embryo transfer (eSET)

• Elective single embryo transfer is the deliberate choice to transfer one embryo during an IVF (in vitro fertilization) cycle even though other embryos are available.
• eSET aims to balance successful pregnancy outcomes with minimizing potential complications for mother and child associated with a multiple pregnancy (twins or more).
• Enhanced embryo selection techniques, such as preimplantation genetic testing (PGT) and out time-lapse incubator monitoring, improve the likelihood of successful pregnancies with single embryo transfers.
• eSET often yields similar or even better pregnancy success rates compared to transferring multiple embryos.
• Not all women are good candidates for eSET when more than one embryo is available, as certain limitations may restrict the transfer of a single embryo.
• Similarly, not all patients want to implant only one embryo, and we have guidelines for honoring such requests.

What is elective single embryo transplant (eSET)?

Elective single embryo transfer (eSET) is the intentional transfer of just one embryo during an IVF cycle when multiple, healthy embryos are available. Ember’s primary goal for IVF when possible is for the mom and her single baby to be healthy. So we highly recommend eSET for that single birth, which decreases the incidence of multiple pregnancies that carry substantial risks for mother and child.

Our approach to fertility treatment

Ember is dedicated to providing clear, comprehensive guidance, including the risks and benefits of every option in fertility treatments so that families can make well-informed decisions. By combining empathy with expert insight, we strive to offer the most appropriate path to parenthood for each patient.

The rationale for the shift to eSET

This choice stands in contrast to historical IVF practices where multiple embryos were transferred to increase the chances of pregnancy and birth. Because multiple eggs are retrieved and fertilized to become embryos, those undergoing IVF often have more than one embryo available.

According to Fertility and Sterility, twin gestations in successful IVF pregnancies in women under age 38 dropped from 23% in 2014 to about 12% in 2017. Still, the rate of twins born following IVF is higher than the rate of twins in non-IVF pregnancies. The desire to reduce the number of multiple pregnancies coincided with the means to do so.

We want patients to know that the eSET procedure does not involve any changes in the way we perform IVF.

Advances in preimplantation genetic testing

As reproductive technology and embryology have advanced, the ability to achieve a healthy birth by implanting just one embryo instead of the past normal practice of implanting two increased. The ability of preimplantation genetic testing (PGT) to evaluate an IVF embryo for genetic defects that often cause failed pregnancies greatly increases the chances of success when implanting a single healthy embryo.

Thus eSET has emerged as the preferred option, allowing couples to approach pregnancy and childbirth more safely and thoughtfully. The American Society for Reproductive Medicine (ASRM) recommends this as the goal for embryo transfer.

Ember’s eSET edge: time-lapse incubator for embryos

There’s a big difference between Ember Fertility Clinic and many other clinics in adapting to the eSET trend. We are equipped with time-lapse incubators for embryos that monitor and record the entire process of embryo development. This precise monitoring through the critical one-week embryo growth process enables our embryologists to better determine which embryo(s) has the highest potential to result in a pregnancy and healthy child.

Clinics that do not have time-lapse incubator monitoring rely on the PGT results, plus standard embryo grading based on one point in the entire process. This inhibits their ability to select the best prospects for frozen embryo transfer.

With our advanced equipment and knowledge, Ember can do better in embryo selection for eSET.

That said, not all patients are suitable candidates for eSET (see below for suitable candidates). Some individuals may also only have one embryo available, so transferring the one is not considered an elective situation.

eSET reduces risks from carrying twins, triplets or more

Pregnancies with multiples, either twins, triplets or more fetuses, carry increased health risks for both the mother and babies. For the mother, these can include high blood pressure, gestational diabetes, preeclampsia, hemorrhaging and a greater likelihood of needing a C-section delivery. The mother of a multiple pregnancy has a higher risk of miscarriage. These can add to emotional stress during and after the pregnancy.

For the children, risks are primarily related to premature birth, which can lead to low birth weight, respiratory issues and developmental delays. The risk of death is also greater for a child in a multiple pregnancy. And after live birth, the child is more likely to require intensive care.

Related Reading: How many IVF cycles does it take?

Frequent eSET related question: Can I have twins if I want?

While Ember promotes eSET when applicable, we do not mandate it. One of the most asked questions by IVF patients is, “Can I have twins if I want to?”

We do offer multiple embryo transfer, but only with a full understanding of the potential risk. We do require a signed informed consent agreement.

Which patients are suitable for transferring multiple embryos?

The answer is highly related to the age of the woman and the genetic quality of the embryo. If an embryo has the correct number of chromosomes in a pair (a euploid embryo), we always transfer just one embryo regardless of the woman’s age. If the embryos are aneuploid (an abnormal number of chromosomes), which are more likely to result in failed pregnancy or birth defects, the general rule is the older the patient and/or the worse the quality of embryos, the higher the number of embryos that can be transferred.

ASRM notes that in addition to embryo euploid integrity, other factors suggesting success in transferring more than one embryo include a previously successful IVF birth and existence of high-quality embryos at the blastocyst stage.

ASRM approves of these guidelines by mother’s age for numbers of embryos to transfer when the embryos are not euploid or are deemed unfavorable:

• 35 or younger: ≤ 2
• 35-37: ≤ 3
• 38-40: ≤ 4
• 41-42: ≤ 5

Our fertility specialist will work with each patient desiring to implant more than a single embryo, adhering to ASRM guidelines.

Factors for choosing eSET

Quality of the embryo is a major consideration. Our embryologists evaluate each embryo looking for specific signs of healthiness. We also encourage patients to utilize PGT to identify genetic abnormalities.

Our criteria for eSET candidates are those who are likely to have a successful birth of a healthy child with just one embryo being implanted. Our fertility specialist Dr. William Freije is skilled at identifying such candidates through information gained in discussion, examinations and testing.

The best candidates for eSET are women who meet the following criteria:

• Are under age 35, as they typically have higher egg and embryo quality.
• Have multiple top-quality embryos available.
• History of successful IVF cycles.
• First-time IVF cycle participants.
• Are using embryos from donated eggs.
• Do not have a history of miscarriage.
• Have a favorable uterine environment.

While eSET offers many advantages, couples should carefully consider their health history, financial means and age among other factors when deciding on their fertility journey. Our team will help advise throughout, including whether or not eSET is the best path forward.

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Dr. William Freije’s expertise in fertility treatment

Dr. Freije is double board certified in reproductive endocrinology & infertility (REI) and OB-GYN.

He has a Ph.D. in human genetics, giving him exceptional insights into this important factor of advanced maternal age fertility challenges.

He is an assistant clinical professor at UCLA’s department of obstetrics and gynecology, helping train the next generation of OB-GYNs.