A number of patients told us that, when they raised with physicians at other IVF centers CHR’s opinion that extended blastocyst-stage embryo culture, at best, should be offered only to good-prognosis patients, they were told that CHR made these recommendations “because CHR’s laboratory was not good enough in culturing embryos to blastocyst stage.”
This is, of course, complete nonsense. CHR would not have the IVF pregnancy rates and live birth rates it transparently reports (in contrast to many other IVF centers) in likely the most adversely selected patient population in the U.S. (if not the world), without an embryology laboratory of superior quality.
It, nevertheless, was nice to see that Fertility & Sterility, the official organ of the American Society for Reproductive Medicine (ASRM) in the by Richard M. Legro, MD (from Penn State College of Medicine in Hershey, Pensylvania) well edited front matter in the August issue (http://dx.doi.org/10.1016/j.fertnstert.2016.06.031), finally, addressed this important issue in an invited piece written by Demián Glujovsky, MD from Buenos Aires, Argentina, and Cynthia Farquhar, MD from the University of Auckland, New Zealand (http://dx.doi.org/10.1016/j.fertnstert.2016.06.029).
Dr. Glujovsky is, of course, the principal author of a meta-analysis, comparing cumulative pregnancy chances after cleavage-stage (day-3) and blastocyst-stage (days-5/6) embryo transfers (Cochrane Database Syst Rev 2012;11:CD002118), which we widely quoted in these pages in support of our position. He and co-authors now published a follow-up meta-analysis (Cochrane Database Syst Rev 2016;39:CD002118), which, once again, confirmed how limited studies on this subject are and how poor their quality is.
They were, however, with a reasonable level of certainty, able to confirm that blastocyst-stage transfer increased live birth chances per embryo transferred. But in contrast to earlier studies, there was no mention on whether this finding, as previously suggested in a number of studies, applied only to good-prognosis patients. They did demonstrate that patients undergoing blastocyst-stage embryo transfer ended up with significantly fewer embryos for cryopreservation and that 2- to 4-times as many women do not reach embryos transfer with blastocyst-stage than with cleavage-stage transfers. They, however, were no longer able to demonstrate outright higher cumulative live birth rates with cleavage-stage transfers, as they reported in their 2012 study.
These mildly revised data, as the authors point out, are difficult to interpret, not the least because of small study numbers and their poor quality. Since the updated study, however, does not differentiate between good, intermediate and poor prognosis patients, the reported results, most likely, still suggest that poor prognosis patients are not advised to go for extended embryo culture because they usually produce only small egg and embryo numbers. Seeing embryo numbers further reduced through extended embryos culture makes no sense.
In average prognosis patients, outcomes most probably are similar with both culture methods and in good prognosis patients with large embryo numbers, there may be an outcome advantage in extended culture to blastocyst stage. CHR, therefore, will not change its current policy of, in principle, avoiding extended culture for poor and intermediate prognosis patients but we, of course, will follow the literature and change our approach, should good evidence in the future suggest otherwise.
This is a part of the September 2016 CHR VOICE.