How compliant are member clinics in following ASRM/SART blastocyst stage transfer guidelines?: an analysis of 34,140 fresh first autologous cycles from the SART registry

Abstract

ASRM and SART regularly update guidelines on the maximum number of embryos to transfer per cycle in various age groups. Providers/patients, however, often elect to transfer more than the recommended number of embryos, which can lead to an unnecessary increase in the number of multiple pregnancies. The objective of this study was to determine the prevalence of blastocyst transfer cycles that do not conform to current recommended embryo transfer (ET) limits and assess the impact of noncompliance on multiple pregnancy rate (MPR) in first IVF cycles with a favorable prognosis. Retrospective cohort study. 34,140 first fresh autologous IVF cycles in women under 43 undergoing blastocyst stage (day 5 and 6) ET from the 2011-2012 SART registry were stratified into cohorts based on ASRM defined age bins. Cycles were classified as compliant (C) or noncompliant (NC) based on their adherence to published 2009/2013 guidelines based on first IVF cycles with a favorable prognosis. Main outcomes were the percentage of C and NC cycles in each age group as well as the MPR (≥2 fetal heart beats on ultrasound) in each of these groups. Secondary outcomes included clinical pregnancy rate (CPR), live birth rate (LBR), and singletons. Data were analyzed using two-sided Welch's t-test for each age category and the Benjamini-Hochberg procedure was used to control the false discovery rate. The vast majority of cycles performed in women <35 were NC (71%) and resulted in significantly higher CPR, LBR and MPR compared to C cycles. When women under 35 underwent a NC ET cycle, MPR was significantly higher compared to C cycles. Far fewer cycles were NC in the older age groups. In women >35, NC cycles demonstrated lower LBR but significantly higher MPR (Table). In a sub-analysis of C cycles among patients 35-37 and 38-40 years, transferring two embryos resulted in a higher LBR than transferring one embryo (50.4% vs. 40.9%, p<0.001 and 42.1% vs. 30%, p<0.001, respectively). However, the MPR was also significantly higher in each of these age groups for two versus one embryo transfer (40.5% vs. 1.7%, p<0.001 and 34% vs. 2%, p<0.001, respectively).Tabled 1Pregnancy Outcomes and Multiple Pregnancy Rate based on Age and Number of Embryos Transferred<35yo35-37yo38-40yoCompliant (1 ET)Noncompliant (≥2 ET)Compliant (1-2 ET)Noncompliant (≥ 3 ET)Compliant (1-2 ET)Noncompliant (≥ 3 ET)n61211500868644043524897Compliance (%)297194.45.679.720.3ET (mean)121.73.11.83.1ET (range)12-51-23-51-23-7CPR (%)57.664.8 **5846 **51.645.7 *LBR (%)4956.4 **47.938.4 **39.833.3 **Singletons (%)97.251.7 **68.252 **70.964.3 *MPR (%)2.848.3 **31.848 **29.135.7 **=p Open table in a new tab *=p Among all age groups, women <35 are at highest risk of undergoing a NC cycle resulting in a significantly higher MPR. Adherence to ET guidelines in women under 35 would result in an immediate and significant reduction in national MPR. Furthermore, if the optimal measure of success of IVF is a singleton delivery, guidelines in women over 35 need to be modified to recommend single blastocyst transfer in first cycles.