Patient Factsheet teaser

Why would I choose to have elective single-embryo transfer (eSET)?

Revised 2023


When a woman undergoes in vitro fertilization (IVF), she is usually given medicines to stimulate her ovaries to develop more than one egg at a time. Typically, all the eggs that are collected are fertilized with sperm and then are monitored to see if any develop into embryos. One or more embryos are then transferred back to her uterus. The recommendation of how many embryos is usually based on her age, history and how many embryos there are available to freeze.

What is elective single-embryo transfer or eSET?

Elective single-embryo transfer (eSET) is when a woman undergoing IVF chooses to have a single embryo transferred when multiple embryos are available.

Why only a single embryo?

The primary goal of eSET is to decrease the multiple pregnancy rate associated with IVF. In the United States, approximately 30% of IVF pregnancies are twin pregnancy, and another 3% to 4% result in a triplet or higher order (4 or more implanted embryos) pregnancy. Transferring more than one embryo increases the chance of having a multiple pregnancy (twins, triplets, etc.).

Why would I want to avoid having a multiple pregnancy?

A multiple pregnancy is significantly more dangerous for both the woman and the fetuses. It often leads to premature delivery. Babies born prematurely are at risk for serious short- term and long-term health problems such as cerebral palsy, long-term lung and gastrointestinal problems, and even death in the first few months of life. For more information about the risks to mothers and babies, please see the ASRM booklet titled Multiple pregnancy and birth: twins, triplets, and high-order multiples.

Are there other ways to prevent a multiple pregnancy with IVF?

Early in pregnancy, the number of fetuses can be decreased in order to increase the chances of having a baby or babies delivered as close to full-term as possible. The procedure is called multifetal pregnancy reduction. This procedure may not be an acceptable alternative for many couples and there are risks, including the possibility of losing the entire pregnancy. eSET reduces the chance you will have a multiple pregnancy and need to consider this procedure.

Am I a good candidate for eSET?

Only women with the best prognosis for a pregnancy should be considered for eSET. Many factors contribute to a successful outcome, and eSET is usually recommended for women who: are younger than 35 years are undergoing their first assisted reproductive technology (ART) cycle have had a successful pregnancy in a previous ART cycle have a relatively large number of high-quality embryos have embryos available for cryopreservation (freezing to use in a later cycle).

How is the best embryo chosen?

To pick the highest-quality embryo to transfer, the laboratory grades each embryo based on its appearance. This assessment includes looking at the number and size of the cells, the rate of development, and other factors. Different grading systems are used and may vary from clinic to clinic. Systems also differ depending on whether the embryo is being evaluated in the cleavage or the blastocyst stage. No method can reliably predict which embryo will produce live offspring. Some programs are investigating new techniques for finding the best embryo, such as testing to see if an embryo is genetically normal. It is not yet known if these methods will help increase pregnancy rates.

How successful is eSET?

In women who are considered good candidates, eSET has shown excellent pregnancy rates. There is a small decrease in overall pregnancy rates after eSET because it is sometimes offered to women who are not good candidates for eSET (for instance, patients who have not succeeded in getting pregnant with IVF in the past and/or patients who are older than 35 years). However, freezing extra embryos and transferring in later cycles can give a comparable pregnancy rate without the risks associated with twinning. The benefit in choosing eSET is a dramatic drop in multiple pregnancy rates—overall, twin rates after eSET are around 1%-2%. Whether to use eSET is a decision each patient should make after talking with her reproductive health professional. The patient should discuss her concerns and ask for clinic-specific success rates with eSET to assist in the final decision-making.

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Resources For You

The American Society for Reproductive Medicine (ASRM) is committed to providing patients with the highest quality information about reproductive care.

Multiple Births or Multiple Gestation

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Challenges of Parenting Multiples

There are many psychological, social, and economic issues associated with multiple pregnancies. View the Fact Sheet
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Multiple Pregnancy and Multiple Births: Understanding the Risks for Mothers and Babies

Research shows that women carrying twins and triplets are at greater risk for complications than women carrying one baby. Watch Video
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Multiple Pregnancy

Multiple Pregnancy is a pregnancy that includes more than one fetus and is much more common today than in the past. As attractive and efficient as a multiple pregnancy may sound, there can be significant risks associated with carrying, delivering, and raising multiple children. The goal is one healthy baby at a time. Watch Video
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Oral medicines for inducing ovulation

Some women may need medicines to help them ovulate (release eggs). View the fact sheet
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What do I need to worry about with a multiple pregnancy?

Women who take fertility medicines to get pregnant have a higher chance of having more than one fetus in a pregnancy. VIew the fact sheet
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Multiple Pregnancy and Birth: Twins, Triplets, and High-order Multiples (booklet)

Multiple births are much more common today than they were in the past. Read the booklet
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Fertility Drugs And The Risk of Multiple Births

Infertility treatments that cause multiple eggs to develop make it more likely that you will become pregnant with twins, triplets, or more. This is called multiple gestation. View the Fact Sheet
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Side effects of injectable fertility drugs (gonadotropins)

Gonadotropins are fertility medications given by injection that contain follicle-stimulating hormone (FSH) alone or combined with luteinizing hormone (LH). View the fact sheet
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Multiple Births or Multiple Gestation Infographics

ASRM has prepared infographics to illustrate the subject of Multiple Births or Multiple Gestation better. View the infographics

Embryo Transfer

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IVF-assisted pregnancies constitute 2.5% of all births in 2022

In 2022, the number of babies born from IVF increased from 89,208 in 2021 to 91,771 in 2022. This means that 2.5% of births in the US are a result of ART.

View the Press Release
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ASRM provides testimony to Senate Judiciary Committee on threats facing IVF

ASRM shared with the Senate Judiciary Committee the dangers to reproductive medicine nearly two years after the Dobbs decision.

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Fresh and Frozen Embryo Transfers

The goal of this SART micro-video is to explain fresh and frozen embryo transfer. Watch Video
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SART FAQ About IVF

Created by the Society for Assisted Reproductive Technology (SART) the following are answers to frequently asked questions concerning in vitro fertilization (IVF). Learn the facts

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