Transfer of 2 Embryos Using a Double-Embryo Transfer Protocol Versus 2 Sequential Single-Embryo Transfers: The Impact on Multiple Pregnancy

Abstract

Introduction: Assisted reproductive technologies (ARTs) are associated with potential risks, mainly related to multiple pregnancies, which are around 20% to 25%. Iatrogenic multiple pregnancies due to ovarian stimulation with multiples embryos transferred can be avoided by the elective single-embryo transfer (eSET), a growing practice worldwide. Adequately applied eSET, which impact on the incidence of complications without compromising treatment success, is still a challenge. The aim of this study was to compare the cumulative success rates of elective transfer of 2 embryos when transferred one by one (eSET), versus the success rates of elective double-embryo transfer (DET) in a single procedure, in a good prognosis population.

Methods: This study evaluated 610 good prognosis infertile couples undergoing ART, split into 2 groups: eSET group which included those receiving first eSET (n = 237) and for those who did not become pregnant, they could receive a second frozen-thawed SET; and eDET group (n = 373) who received elective transfer of 2 good quality embryos in the first transfer.

Results: Clinical pregnancy outcomes after a transfer of 2 embryos were similar between the groups (DET: 46.6% vs accumulated SET: 45.9%; P = .898). Multiple pregnancy rate was significantly lower in the group receiving transfer of 2 embryos, one by one, compared to DET (DET: 32.2% vs accumulated SET: 6.7%; P < .001).

Conclusions: The eSET policy should be stimulated for good prognosis couples, as it maintains the accumulated clinical pregnancy rates, avoids multiples pregnancies, and consequently the maternal and neonate complication and indirect costs of treatment when considering spending on the obstetrics are reduced.

Keywords: double-embryo transfer; in vitro fertilization; multiple pregnancy; pregnancy rate; single-embryo transfer.