Single Embryo Transfer Policy Research Articles

Laboratorial Rules for Choosing the Elective Single Embryo to be Transferred: Morphological Parameters

The high incidence of multiple pregnancies is a major side effect of assisted reproductive technology that has recently given rise to justified criticism from different sides. The only efficacious measure to reduce the incidence of twin pregnancies is a policy of single-embryo transfer. The objective of this study was determined the main morphological non-invasive parameters able to select embryos with highest implantation potential to be transferred in an elective single embryo transfer (eSET) program.

Emerging drugs in assisted reproduction

Infertility affects ∼ 15% of couples of reproductive age. In assisted reproductive technology (ART), medications play a crucial role in stimulating ovaries to produce several oocytes and prepare the endometrium to be receptive after replacing one or more embryos into the uterine cavity. The availability of recombinant human follicle stimulating hormone, luteinising hormone and human chorionic gonadotrophin; of gonadotrophin-releasing hormone (GnRH) agonists and antagonists; and of luteal supplementation with progesterone have allowed the tailoring of several stimulation schemes, which have enhanced the pregnancy outcome after ART treatment. However, the remaining risk of ovarian hyperstimulation syndrome, the still low implantation rates, the unacceptably high rates of multiple pregnancies and the daily parenteral administration of medications do not constitute the features of a patient-friendly procedure. Therefore, a number of molecules with gonadotrophin-like activity, inhibition of GnRH receptor ability, or endometrium receptivity enhancement properties are currently under active investigation. Orally bioactive therapeutic preparations, in particular, may revolutionise in vitro fertilisation (IVF) treatment in the near future. Nevertheless, the implementation of mild ovarian stimulation protocols with single embryo transfer policy and further development of oocyte in vitro maturation techniques may lead to a less drug orientated IVF treatment.

Elective single embryo transfer (eSET) policy in the first three IVF/ICSI treatment cycles

Elective single embryo transfer (eSET), applied in the first or second IVF cycle in young patients with good quality embryos, has been demonstrated to lower the twin pregnancy rate, while the overall pregnancy rate is not compromised. It is as yet unclear whether eSET could be the preferred transfer policy in all treatment cycles, or that it should be restricted to the first or first two cycles. eSET policy (when two or more embryos were available, at least one of them being of good quality) was offered to patients younger than 38 years in the first three treatment cycles. Retrospectively, treatment cycle outcome was studied. In 326 patients, 586 treatment cycles were performed (326 first, 168 second and 92 third treatment cycles). In 65 cycles (11%), eSET could not be applied because there was either no fertilization, or only one embryo available. In the remaining 521 cycles, eSET was performed in 111 cycles (19%), while in 410 cycles, no good quality embryo was available resulting in the transfer of two embryos (double embryo transfer, DET). No significant differences in ongoing pregnancy rates after transfer of fresh embryos were observed between eSET and DET in the first (both 33%), second (36 and 23%, respectively) and third treatment cycles (20 and 24%, respectively). In significantly more eSET cycles compared to DET cycles, could embryos be frozen. This resulted in a significantly higher cumulative pregnancy rate after eSET compared to DET. In patients younger than 38 years with at least one top quality embryo, eSET can be the transfer policy of choice in at least the first three treatment cycles, since the pregnancy rates obtained in each treatment cycle are comparable to those after DET.

Toward single embryo transfer policy

Toward single embryo transfer policy

Single-embryo transfer.

The high incidence of multiple pregnancy is a major side effect of assisted reproductive technology that has recently given rise to justified criticism from different sides. The reasons for the high incidence of multiple pregnancies are discussed and a brief review is given of the steps that have been proposed to solve or at least reduce the problem. In this article, attention is particularly focused on the prevention of twin pregnancies because in terms of perinatal morbidity and associated costs, they outweigh the effect of high-order multiple pregnancies when expressed in absolute figures. The only efficacious measure to reduce the incidence of twin pregnancies is a policy of single-embryo transfer. We report on our experience with elective single-embryo transfer in good prognosis patients (age <37 years, first two in vitro fertilization (IVF) cycles and at least two embryos of high quality). About one-third of the couples meeting these criteria agreed to have a single embryo transferred, at least during their first IVF cycle. Pregnancy rates in women who had an elective single-embryo transfer (more than one high-quality embryo available) were only slightly lower than those in the group with elective double (i.e., more than two high-quality embryos available) transfer (37.9 vs. 40.0%) but the incidence of twins was 0.0 versus 27.1%. This strategy resulted in a substantial decrease of the twin pregnancy rate from 27.0 to 14.9%, without affecting the overall pregnancy rate. The conditions that are to be fulfilled before this policy can and will be applied on a large scale are discussed.