Elective Single Embryo Transfer - Notes from this year's ASRM meeting
Posted Oct 21 2009 12:00am
At the annual American Society for Reproductive Medicine meeting one of the many courses I attended was one entitled "Elective Single Embryo Transfer". Perhaps no issue in assisted reproductive technologies (ART) is as controversial as the selection of the optimal number of embryos for transfer. Single Embryo Transfer or SET is a method being heavily promoted by the fertility specialists to reduce the incidence of a multiple getstation. Of course, the recent New York Times article about twins that were born with severe deficits was a source for discussion ("The Trouble With Twin Births" Oct. 11, 2009 Opinion").
Indeed, in current years the number of triplets resulting from ART has diminished; but the number of twins has not declined. The most recent guideline published by SART indicates that the number of embryos to transfer in women age 35 and under is 1 - 2 embryos for "favorable prognosis patients and 2 for all others".
The panel consisted of two Physicians and a PhD Embryologist. Both Physicians came from states where IVF is a mandated benefit, so their patients don't pay out of pocket. They presented their data and arguments for proposals to enact a SET policy on good prognosis patients under 38 years old. They condemned all multiple gestations, including twins, because of the increased costs of the medical care.
The main data they showed to support their argument was that cumulative pregnancy rates (PR) (fresh transfer plus frozen attempts) were the same as PR from transferrring 2 embryos (DET) in one cycle. Transferring SET had a lower PR than transferring DET in a single cycle if you did not add the frozens. Because IVF was mandated, the extra cycles were at no extra cost. The other point that they made was that if the patient failed in the 1st cycle, they transferred 2 (DET) embryos in the subsequent cycle. So in essence, in order to achieve the same PR as the DET in 1 cycle, they had to transfer 3 embryos over two or more cycles.
Their final point was that as reproductive specialists and physicians, we are bound to an ethic of "do no harm" and having a multiple gestation is "harm" as explained in the NY Times article. They professed that we should choose for our patients to transfer only one embryo and not let the emotions and "desperation" of patients to choose more than one embryo for a higher PR.
Personally, I too strive for a singleton pregnancy for all my patients. That is the ultimate goal. I am in favor of SET if the PR per cycle is equivalent to DET. We, ASRM, SART and reproductive specialists, are trying to move toward SET as the gold standard. But, we are not there yet! And, when patients have to pay for their cycles, as they do in California, I believe that we also have an obligation to them, as the consumer, to give patients the highest chances of success for the least cost. A "cumulative PR", especially when more than one embryos is transferred in subsequent cycles, with a higher twin PR, is NOT equivalent. This is a fudge of statistic and not truthful counseling.
Also, one has to remember that the NY Times article is an anecdote about a specific couple and should not be interpreted as the "majority" or "usual" outcome of patients or twins. It is absolutely not. With the advances in Obstetrics and Perinatology, most twins deliver at term and do fine, and have no deficits. We should therefore not fear twin gestations. A NY Times article such as the one recently published, is biased and sensationalized, and not based on scientific evidence. Triplets or more is a different story, however, and should strongly be avoided.
In addition, we Do Not have the knowledge or ability to choose the ideal embryo at this time. It is still a best guess. We choose based on external characteristics "best looking" but that doesn't guarentee a perfect internal structure. Many of us have had terrible looking embryos turn into pregnancies and beautiful children. So in fact, although we think we know best for the patient, we may not be doing the best for patients if we limit their choices.
So, I think that DET may still be the best for the patient at this time, in order to give patients the highest chances for success per cycle with a small twin risk and even smaller twin deficit risk. I don't think that patients should be forced into SET but should be honestly and comprehensively counseled regarding the potential risks of twins (as it is, most of our patients are already taking an increased risk of genetically abnormal babies due to age in attempting pregnancy). They the patients should be allowed to choose without interference from the Physician or the Government. After all, they are paying for it. In states or countries where their insurance or government is the payor, then it can be mandated by regulation, and the insurance or government has the right to decide instead of the patient.
When the technology reaches the point where we can accurately distinguish between good and bad embryos with certainty, and SET offers the best PR for the patient, meeting our obligation to the patient, then it will be time to only transfer one embryo per cycle. Until then, we can keep this as our goal and do the best that we can with the information that we have to work with currently, and strive to reduce the higher order multiple PR (triplet or more). We should strive for singletons but allow twins. We cannot forget that success is what serves our patients best.
Edward J. Ramirez, M.D., FACOG
Executive Medical Director
The Fertility and Gynecology Center
Monterey Bay IVF Program
Monterey, California, U.S.A.
for additional information check me out on Facebook and Twitter with me at @montereybayivf