Elective Single Embryo Transfer

With recent technological advances in Assisted Reproductive Technology (ART), pregnancy rates after IVF have increased in clinics throughout the country. But this success has been accompanied by at least one unintended consequence --- a dramatic increase in multiple births. In fact, over 30 percent of IVF pregnancies result in a twin pregnancy. Another 3 to 4 percent are triplets or more.

On the surface, to many IVF patients, having twins seems nothing less than exciting. And because this has been the prevailing public attitude in recent years, patients not only are open to the possibility of twins but also often are seeking twins. This trend is troubling to many physicians.

“Patients commonly ask for two embryos at transfer,” Lee Hickok, MD, of Pacific NW Fertility, says. “They just don’t understand that twin pregnancies are much higher-risk pregnancies than singletons. So an important part of our job is to educate them.”

Hickok and his colleagues at Pacific NW Fertility, and many other U.S. infertility clinics, are on a mission to reduce multiple pregnancies.

“By slowing down that decision making process and educating our patients about Elective Single Embryo Transfer (eSET), we can better help them understand what they may face with a twin pregnancy, and have safer and more successful outcomes,” Hickok says.

Twin pregnancies are at increased odds of ending in premature delivery and the subsequent complications that can go along with them. Pre-term babies have higher risk of cerebral palsy, long-term gastrointestinal problems, life-long respiratory developmental issues, neurologic problems and, most sobering, an increased chance of death. Mothers as well have higher risk of maternal complications.

In almost all cases, twins occur as a result of more than one embryo being transferred into the uterus of female patients. And most commonly, the twins are the result of a multiple embryo transfer into a patient who already has a very high chance of becoming pregnant. The age of the mother, the age of the eggs (in the case of a donor being utilized), the quality of the embryos, and the quality of the laboratory can all lead to an increased chance of pregnancy and consequently twins when more than one embryo is transferred.

“Not so long ago we wanted to transfer two embryos --- or more --- because we wanted to maximize the chance of one taking,” Hickok explains. “But these days, with the advances in the lab and the improved pregnancy rates we just don’t need to do that,” he says.

Chromosomal screening of embryos is also now available and provides for another level of embryo selection, improving pregnancy rates and further encouraging patients to undergo eSET.

The American Society for Reproductive Medicine (ASRM), the field’s national governing body, agrees. The organization is working with clinics to reduce the twin rate from the current high rate of 60% in some U.S. clinics to below 10 percent and recommends a single embryo transfer in most cases.

“It’s become a big problem,” Hickok says. “Patients pressure doctors for success. Fertility treatment is expensive and patients see twins as a “two for one” outcome – an instant family with one pregnancy. It’s our responsibility to educate the patients about risks and share the goal of one healthy pregnancy at a time.”

While patients need education about eSET, physicians also can benefit from learning more about the risks associated with multiple embryo transfer and the overall benefits to patients from this single embryo option. ASRM says the ideal candidate for eSET is:

  • A woman less than 35 years
  • first assisted reproductive technology (ART) cycle
  • or previous ART success
  • or a relatively large number of high-quality embryos generated
  • or having embryos available for cryopreservation
  • “Good programs can move from transferring multiple embryos to transferring one and still have very good success rates,” Hickok insists. “There will be a slight decrease in the pregnancy rate but that small difference is easily offset by the decrease in so many of the risks that come with multiples.”

    Pacific NW Fertility’s success rates using eSET are only 5 percent lower than with multiple embryo transfers.

    Hickok says making the number of embryos a couple needs to build their family, and not many more, if at all, is very attractive to patients. And it makes eSET that more appealing.

    There is a way to go before this issue is resolved, Hickok says. But clinics, like his own Pacific NW Fertility, are helping to change outcomes and adapting new best practice protocols that take all parties’ well-being into consideration --- including the babies that will come as a result of the ever-changing field of reproductive technology.

    We have worked with, and been patients at, 5 fertility clinics and this clinic is far and above the best experience we have had. Kind, talented, flexible staff. We don't feel like a number. Wish we had started out with you.

    2015 Anonymous Patient Survey
    Pacific NW Fertility Patient

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