Defining ART success

To the Editor:

We are very pleased to note Dr. Meldrum’s “Conceptions” piece (1), following our recent report (2), reaffirming our main conclusion that the current IVF outcome reporting system requires a major overhaul. Dr. Meldrum, furthermore, emphasizes other points raised in our article, including the need for ART reports to incorporate maternal and perinatal outcomes rather than just pregnancy rates in defining assisted reproductive technology (ART) success, to better align reports with patient interests (3). We also agree with basing outcome reports on the total reproductive potential (TRP) of each initiated in vitro fertilization (IVF) cycle, which includes the initial fresh cycle plus subsequent frozen transfers, a process feasible from the current Society for Assisted Reproductive Technology (SART) database (4).

Dr. Meldrum’s main proposal of reporting outcome data on a per embryo transfer basis will, however, not solve the problem of outcome data manipulation in IVF, which our report brought into the open (2). In fact, reporting outcome data on a per embryo transfer basis may actually further exacerbate exclusion of poor prognosis patients who start cycles but, for various reasons (embryo banking with unsuccessful subsequent thaw, all embryos degenerate in extended day-5/6 culture, all embryos aneuploid after preimplantation genetic screening (PGS), etc.), never reach embryo transfer. Exactly these kinds of exclusions currently allow a small minority of reporting centers to disproportionately select out patients with low pregnancy potential and, thereby, to manipulate pregnancy rates in the centers’ favor (2).

Letter to the editor regarding “The status of public reporting of clinical outcomes in assisted reproductive technology”

To the Editor:

We commend Kushnir et al. for their detailed analysis of the publicly available Society for Assisted Reproductive Technology (SART) report in the article “The status of public reporting of clinical outcomes in assisted reproductive technology” (1). SART continues to believe that any use of the ART report to make direct comparisons of outcomes between clinics is not valid and is inappropriate. The goal of the report is to facilitate reasonable estimation of the success rate at a given clinic. Unfortunately, recent evolution of clinical practice has made the reasonable estimation of success per cycle start much more difficult.

The exclusion of “banking” cycles from the denominator of the report is an unintended consequence of our common sense handling of true “fertility preservation” cycles. The outcomes report would be misleading if it included cycles with no intention for embryo transfer in the near future (for example, cycles conducted to obtain eggs or embryos prior to chemotherapy). SART has identified the need to distinguish fertility preservation from “short-term” banking. The indications for short-term banking (such as PGD, endometrial receptivity) are outlined in the manuscript; however, other indications for short-term banking exist (for example, risk for OHSS, polyps, etc.). We fully agree that the outcomes of these cycles should be accounted for in the Clinic Summary Report. The SART Registry Committee and SART Executive Council have discussed this at length, and we have sought input from our members. We do not believe that simply indicating the number of embryo banking cycles is adequate. SART has met with the Centers for Disease Control and Prevention (CDC), with whom we have a long-standing collaboration, to discuss what our options are for including banked cycles in outcome reports.

Public reporting of clinical outcomes in assisted reproductive technology

To the Editor:

We read the article “The status of public reporting of clinical outcomes in assisted reproductive technology” by Kushnir et al. (1) with great interest. As stewards of the National ART Surveillance System (NASS), we are always striving to improve data collection and public reporting of clinical outcomes of ART, as required by the Fertility Clinic Success Rates and Certification Act (FCSRCA) of 1992. The article refers to a recent but increasing trend of short-term embryo banking (cycles in which all embryos are created with the intent of cryopreservation for subsequent transfer in frozen/thawed cycle(s) in the next few months) following advances in cryopreservation techniques (2). Some of the potential reasons to delay embryo transfer include: embryo accumulation from several short-term embryo banking cycles to allow better choice of good-quality embryos, desire to avoid potentially negative effects of stimulation on implantation/pregnancy rates and fetal development, and need to wait for the results of preimplantation genetic screening. In contrast, long-term embryo banking cycles are generally used for fertility preservation for patients undergoing gonadotoxic medical treatments or for those who wish to delay childbearing for other reasons. Although NASS is currently unable to distinguish between short- and long-term banking cycles, we note that the total number and percent of embryo banking cycles in the U.S. has increased dramatically during recent years (Figure).

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Since FCSRCA requires public reporting of ART success rates, embryo banking cycles (which by definition do not result in clinical outcome) are not shown in the national or clinic-specific pregnancy success rates tables. However, all embryo banking cycles fit the definition of ART and are required to be reported to the Centers for Disease Control and Prevention (CDC). Thus, we believe that the authors incorrectly assumed that embryo banking cycles are “unreported” or “excluded” by clinics. The outcomes of all frozen/thawed embryo transfers have been publicly reported for cycles started during or after 1995, the first year national ART surveillance began. In addition, reporting of embryo banking cycles is validated annually (3).