When we first started doing IVF in the 1980’s the state of the science, like culture techniques and only being able to sustain embryos in the lab until Day 2 or 3, required us to transfer multiple embryos to have any decent chance of success. One of the big problems we faced was the risk of high order multiple pregnancies. The number of embryos to transfer became a large issue. Of course we understood that transferring fewer embryos led to fewer high order multiple pregnancies.
Transferring fewer embryos in appropriate clinical conditions reduces the rate of multiple gestations without impacting live birth rates, according to new recommendations from the American Society for Reproductive Medicine and the Society for Assisted Reproductive Technology.
As scientific advances continue to improve the chance of having a baby through IVF, we are mindful of our goal of helping our patients have a healthy singleton child,” Alan Penzias, MD, chair of the Practice Committee of the American Society for Reproductive Medicine, said in an interview. “Accrued data have led us to revise our recommendations and in many cases advocate for single embryo transfer; thus, our decision to revise the guidance document.”
Dr. Penzias and fellow committee members reviewed national data from 2013 that showed similar pregnancy rates for women aged 42 years and younger who received a single euploid blastocyst or two untested blastocysts. But the risk of twins was significantly reduced with single embryo transfers.
The recommendations state that euploid embryo transfer should be limited to one for women of any age with a favorable prognosis, and for women younger than 35 years regardless of the embryo stage.
Patients aged 35-37 years should first consider single-embryo transfer, and patients aged 38-40 years should receive single-blastocyst embryo transfers if euploid embryos are available, but no more than three cleavage-stage embryos or two blastocysts.
Patients aged 41-42 years should receive single blastocyst transfer if euploid embryos are available, or no more than four cleavage-stage embryos or three blastocysts.
For patients in each age group without a favorable prognosis, the recommendations support transfer of an additional embryo based on individual circumstances and with the condition of patient counseling about the risk of multiples. Additional embryo transfers also may be considered for women who fail to conceive after multiple cycles.
However, “patients with a coexisting medical condition for which a multiple pregnancy may increase the risk of significant morbidity should not have more than one embryo transferred,” the committee members wrote.
The recommendations also call for single-embryo transfer in donor cases where the oocyte donor is younger than 35 years. For patients using frozen embryos, transfers should not exceed the recommended numbers for each age group, and decisions should be based in part on the patient’s age when the embryos were frozen.
The new recommendations will impact clinical practice by providing clinicians with the data they need when counseling patients, said Dr. Penzias, a reproductive endocrinologist in Waltham, Mass., and a clinical professor at Harvard Medical School.
Patients should receive the take-home message that “placing more embryos at once isn’t the best way to achieve their goals,” he said. The recommendations “will help to continue the trend toward single-embryo transfer in an ever-widening group of patients,” he noted.
At RPMG we have been moving toward single embryo transfer for years.