Elective Single Embryo Transfer (eSET): Rethinking the “One Pregnancy and Done” Philosophy
Many couples with infertility both desire and welcome the birth of twins, thus affording an instant family often after years of frustration, disappointments and inability to conceive adopting a “once and done” motto. Limitations of insurance coverage and increasing competition amongst infertility centers demands that pregnancy be achieved in as few cycles as is possible. Such pressures often culminate in the transfer of multiple high-quality embryos.
As a result, these treatments now are responsible for 50% of twin births and 75% of higher-order births. The inherent risk of a multiple-gestation pregnancy to both mother and fetus(es) alike are not trivial, and increase dramatically when fetuses share a uterus. The most common maternal risks include: pregnancy-associated hypertension, gestational diabetes and Cesarean delivery. The most worrisome obstetric complications include: premature membrane rupture, premature birth, incomplete organ maturation and compromise as well as placental abruption. Both individually and in combination, these issues can cause significant morbidity and possible mortality. Rooted in the desire to promote maternal and fetal well-being, our profession is driven to develop both philosophies and technologic methods that reduce the frequency of multiple gestations and higher order (>2) pregnancies. Ultimately, the goal of ART (assisted reproductive technologies) is the delivery of a single, healthy child.
The most effective means for reduction is the promotion of an elective, single-embryo transfer (eSET). The concept of eSET is not new and is presented as a reasonable response to the high proportion of multiple pregnancies generated. The philosophy of eSET, and the inherent need to maintain pregnancy success while limiting the number of embryos transferred, has called the field to address various aspects of single-embryo transfer. Refinement of both embryo selection techniques and evaluation of patient candidacy for eSET demonstrate that it is effective in maintaining pregnancy rates while reducing significantly the number of higher-order pregnancies. Furthermore, as an application, eSET allows us to study the relationship between individual embryo characteristics and implantation. Expanding our understanding of these intricate processes of embryo development and implantation will afford greater success in the future.
eSET is not just a philosophy but also a viable concept in action. In Europe where eSET is implemented widely, the rates of multiple gestations have dropped. There was no significant decrease in the pregnancy rate although this potential outcome was much feared and anticipated. Our results at The Fertility Centers of New England supports the European experience as patients in whom we have done eSET have a greater than 40% on going pregnancy rate even in women up to the age of 37.
eSET is effective and promotes fetal well-being. These infants have fewer obstetric and neonatal issues. In fact, babies born from eSETs do better than babies born from multiple embryo-transfers even when there is a single fetus in utero. In fact, they perform as well as those singleton infants conceived naturally.
Eagerly, we await wide patient-acceptance of eSET. It is anticipated that patient confidence will grow as we demonstrate both clearly and continually, that it is possible to select the best embryo for transfer. As we work toward bettering reproductive science infertility treatments become more successful; and most importantly, we promote good pregnancies and healthy children.