High multiple pregnancy rates after double embryo transfers in human: a retrospective cohort study.

Abstract

To improve clinical outcomes of human medically assisted reproduction, the transfer of multiple embryos is frequently performed. This leads to high rates of multiple pregnancies. In this study we explored if a cohort of patients can be defined, that benefits from the transfer of two embryos while mitigating the odds of multiple pregnancy by considering female patients' age, embryo quality and embryo cohort quality. In this retrospective cohort study clinical pregnancy rate (CPR), live birth rate (LBR) and multiple pregnancy rate (MPR) after fresh single embryo transfers (SET, n = 245) were compared to those after double embryo transfer (DET, n = 278). Female patient's age, embryo quality and embryo cohort quality were used to explore clinical outcomes in subgroups. Overall, this study found that compared to SET, DET significantly increased the CPR (33.5 % vs 49.6 %, aOR 2.233, 95CI 1.529-3.261, p < 0.001), LBR (24.1 % vs 39.2 %, aOR 2.416, 1.605-3.636, p < 0.001) and MPR (0.0 % vs 25.4 %, p < 0.001). Subgroup analysis based on female age, embryo quality and further stratification based on embryo cohort score revealed that the MPR in all subgroups was high after DET and a subgroup with significantly reduced MPR after DET could not be defined. In conclusion, double embryo transfers are associated with high multiple pregnancy rates that cannot be avoided by considering female patients' age, embryo quality and embryo cohort quality. Single embryo transfer is the most effective way to avoid a multiple pregnancy.