To the Editor:
Dr. David Meldrum proposes a revision of the clinic-specific Society for Assisted Reproductive Technology (SART)/Centers for Disease Control and Prevention (CDC) reporting format to better reflect the current practice of in vitro fertilization (IVF) by combining the outcomes of fresh and frozen embryo transfers in the numerator while making transfer procedure the denominator of choice (1). I concur with the first but disagree with the second part of his proposal, making transfer the preferred denominator without regard to the number of retrievals contributing embryos to the transfer. In addition to accuracy, a reporting system needs to be readily accessible to potential consumers.
With accumulation of eggs from multiple retrievals for a single transfer, this metric fails to differentiate between two distinct scenarios: A) one live birth from one transfer and one retrieval; B) one birth from one transfer following, say, four retrievals (2). Both scenarios generate 100% delivery rate per transfer, but the delivery rate per retrieval is 100% for scenario A but only 25% for scenario B. Such a reporting system would be misleading and leave patients vulnerable to exploitation by volume-driven clinics.
In the case of high responders, a single retrieval may lead to more than one live birth from sequential frozen embryo transfers (FETs), thus elevating the delivery rate per retrieval above 100% unless all births after the first one are censored—a crucial point the author does not address. Read the rest of this entry »