Single vs. double good-quality embryo transfer in fresh cleavage-stage cycles: a propensity score-matched analysis of efficacy and risks

To compare the clinical outcomes of elective single embryo transfer (eSET) and elective double embryo transfer (eDET) using good-quality cleavage-stage embryos in fresh IVF/ICSI cycles. This retrospective cohort study analyzed 5,725 fresh cleavage-stage embryo transfer cycles at Henan Provincial People’s Hospital (September 2016–March 2024). Patients were categorized into Group G (eSET, n = 2,688) and Group GG (eDET, n = 3,037). Propensity score matching (1:1) adjusted for confounders. Primary outcomes included live birth rate, clinical pregnancy rate, multiple pregnancy rate, and neonatal outcomes. Subgroup analyses were conducted based on age and prior treatment cycles. After propensity score matching (2,394 cycles per group), eDET was associated with higher clinical pregnancy (69.76% vs. 52.21%, P < 0.001) and live birth rates (58.77% vs. 43.48%, P < 0.001), but also with a markedly increased risk of multiple pregnancy (35.63% vs. 0.8%, P < 0.001) and preterm birth (23.70% vs. 7.31%, P < 0.001). Among patients under 38 years of age, eDET was associated with higher live birth rates (62.58% vs. 45.23%, P < 0.001), accompanied by a substantial increase in multiple pregnancy risk (36.41% vs. 0.76%, P < 0.001). In patients aged 38–41 years, eDET did not result in a statistically significant improvement in live birth rates (38.20% vs. 26.97%, P = 0.110), while the multiple pregnancy rate remained significantly higher (20.83% vs. 0%, P = 0.008). In patients aged ≥ 41 years, no significant differences in live birth rates were observed between groups. Across different treatment cycles subgroups, eDET was consistently associated with a higher risk of multiple pregnancy. In this retrospective analysis of fresh cleavage-stage good-quality embryo transfers, eDET was associated with higher live birth rates but consistently incurred an increased risk of multiple pregnancy and related adverse outcomes. In the age subgroup of 38–41 years, eDET did not significantly improve live birth rates yet still significantly raised the multiple pregnancy risk. For women ≥ 41 years, no statistically significant benefit of eDET was observed. These findings are descriptive and should not be interpreted as prescriptive recommendations for eDET. In line with current ESHRE guidelines, eSET remains the preferred strategy to optimize safety and resource utilization, and to reduce the public health burden associated with multiple pregnancies.