Equivalency of in vitro fertilization success rates in elective single blastocyst transfer and elective double blastocyst transfer: An example of equivalence methodology in clinical reproductive health

Abstract

Context:When comparing success rates between treatments, it is more appropriate to structure analyses in terms of equivalence rather than traditional analyses that assess differences. Unfortunately, no studies of elective single blastocyst transfer (eSBT) have been conducted in this manner.Aims:The objective of this study was to assess clinical equivalence of in vitro fertilization success rates among patients undergoing eSBT.Settings and Design:A historical prospective study was conducted at a private fertility center.Methods:Medical records were reviewed to identify patients eligible for eSBT. Equivalency of success rates, defined as no more than a 10% difference based on 95% confidence intervals (CIs), was compared between eSBT (n = 125) and eDBT (n = 213) groups.Results:Using traditional analysis techniques, no differences in pregnancy or live-birth rates were seen (eSBT: 84.6% vs. eDBT: 84.5%, P = 0.99; eSBT: 65.3% vs. eDBT: 72.3%, P = 0.23). The 95% CI around the difference in pregnancy rates ranged from –7.9 to 8.1, suggesting clinically equivalent pregnancy rates. Clinical equivalence was not established for live-births (95% CI = −18.5–4.5).Conclusions:Findings suggest comparable pregnancy rates can be achieved in a clinical setting when utilizing eSBT in good-prognosis patients. Although live-birth rate equivalence was not demonstrated, it is thought the additional complications associated with multiple gestations outweigh the potentially higher live-birth rate. The present study highlights the importance of utilizing equivalence analyses when making statements regarding the similarity of two treatments in reproductive health, rather than relying on superiority analyses alone.

Comparison of frozen-thawed embryo transfer strategies for the treatment of infertility in young women: a retrospective study

“…For example, double blastocyst transfer was associated with a nearly 60-fold increase in the probability of gemellary pregnancy (OR:59.933, 95% CI [27.298–131.58]) and a 3.84-fold increase in the incidence of preterm birth (OR:3.840, 95% CI [2.272–6.489]) compared to single blastocyst transfer. Jacobs, Klonoff-Cohen & Garzo (2018) found that single blastocyst transfer has a clinical pregnancy rate similar to double blastocyst transfer. It is well known that premature infants, especially low birth weight infants, have immature organ development.…”

Comparison of frozen-thaw blastocyst transfer strategies in women aged 35–40 years: a retrospective study

“…These factors also increase the risk of neonatal mortality and chronic diseases in adulthood, thus placing a heavy burden on the national health care system and the families involved ( 15 ). It has been argued that the high rate of multiple pregnancy and the additional complications associated with DBT outweigh the high live birth rate associated with DBT ( 16 ). The goal of ART is to achieve a full-term, singleton, healthy live birth, and the number of embryos transferred is a controllable factor that relates to the overall treatment outcome, maternal-fetal safety, and post-pregnancy health.…”

The Effects of Number and Quality of Transferred Blastocysts on Birth Outcomes in Frozen-Thawed Transfer Cycles

“…Contrary to cleavage-stage embryos, extending embryo culture to the blastocyst stage allowed for better evaluation of the implantation potential, yielding a higher IR [2][3][4]. Previous studies have posited that elective single blastocyst transfer could yield comparable clinical pregnancy rates (CPR) for patients with a good prognosis [1,5,6]. Although live birth rate (LBR) equivalence was not demonstrated, it was thought the additional complications associated with multiple gestations outweighed the potentially higher LBR [5].…”

“…Previous studies have posited that elective single blastocyst transfer could yield comparable clinical pregnancy rates (CPR) for patients with a good prognosis [1,5,6]. Although live birth rate (LBR) equivalence was not demonstrated, it was thought the additional complications associated with multiple gestations outweighed the potentially higher LBR [5]. Additionally, frozen-thawed single blastocyst transfers have been found to result in enhanced CPR relative to fresh single blastocyst transfers in ovulatory women with a good prognosis [6].…”