Study question Is there a role for elective single blastocyst transfer (eSBT) in advanced maternal age? Summary answer Double blastocyst transfer (DBT) versus eSBT resulted in higher live birth rates except for those undergoing their first cycle. What is known already Women with advanced maternal age are generally considered poorer prognosis patients with lower live birth rates compared to their younger counterparts. This often results in a higher likelihood of double embryo transfer in this group. This is not without risk as multiple pregnancy is associated with significant maternal and neonatal morbidity especially with advancing maternal age. In older women with blastocysts available for transfer, it is unclear who should be recommended double versus elective single transfer. The concept of the “good-prognosis” older woman remains elusive. Study design, size, duration This was a retrospective observational study looking at 511 IVF/ICSI cycles between January 2010 and January 2020. Treatment cycle details and clinical outcomes were entered prospectively into a dedicated clinic database. Data was retrieved and analysed using SPSS V25. Participants/materials, setting, methods The study was conducted in a large London IVF centre. Data was collected on women aged 40 or above undergoing an IVF/ICSI cycle with eSBT (Group 1, n = 79) or DBT (Group 2, n = 430). Women with more than three previous IVF attempts were excluded. eSBT was defined as a single blastocyst transfer with at least one further blastocyst available for cryopreservation. Subgroup analysis was performed for those undergoing their first cycle. Main results and the role of chance Data from 511 cycles was analysed. The mean age was 40.6±1.2years. The live birth rate was 27%. Group 1 was marginally younger (40.2±0.6 v 40.8±1.2, p < 0.005) and was more likely to be undergoing their first IVF cycle (84% v 68%, p = 0.003). Those in Group 1 had more eggs collected (13.6±7.3 v 11.3±5.5, p = 0.009), more zygotes (8.9±4.7 v 7.3±3.6) formed and more blastocysts frozen (3.4±2.6 v 1.1±1.7, p < 0005). More women in Group 1 had a top quality blastocyst (expansion of > 2 and inner cell mass and trophectoderm of AA, AB, BA or BB) transfer (91% v 71%, p < 0.005). After logistic regression controlling for maternal age, number of previous IVF cycles and blastocyst quality, Group 1 had a lower likelihood of livebirth (aOR 0.550, 95%CI 0.306-0.988) but with a significantly lower multiple pregnancy rate (0% v 24%, p = 0.024). Importantly, for those undergoing their first IVF cycle (n = 359), there was no difference in live birth rate in the two groups (aOR 0.617, 95%CI 0.329-1.156) after controlling for age and blastocyst quality but Group 2 had a higher multiple pregnancy rate (24% v 0%, p = 0.020). Limitations, reasons for caution This study is limited by its retrospective nature putting it at risk of information bias as it relied on accurate documentation of studied variables into the patient database. The study did not examine cumulative birth rates of fresh and subsequent frozen cycles in Group 1. Wider implications of the findings Women should have individualised counseling about number of blastocysts to transfer taking into account their circumstances. Those undergoing their first IVF attempt and with a blastocyst available for transfer, should be counselled that DBT is associated with a higher multiple pregnancy rate with no increase in overall live birth rate. Trial registration number Not Applicable

中文翻译：

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P-282 高龄产妇的囊胚移植：单胚胎移植与双胚胎移植

研究问题 选择性单囊胚移植 (eSBT) 在高龄产妇中是否有作用？总结答案 双囊胚移植 (DBT) 与 eSBT 相比，导致更高的活产率，但接受第一个周期的除外。众所周知，与年轻女性相比，高龄产妇通常被认为预后较差，活产率较低。这通常会导致该组中双胚胎移植的可能性更高。这并非没有风险，因为多胎妊娠与显着的孕产妇和新生儿发病率有关，尤其是随着孕产妇年龄的增长。对于有可供移植的囊胚的老年女性，尚不清楚应该推荐谁进行双重移植与选择性单次移植。“预后良好”的老年女性的概念仍然难以捉摸。研究设 使用 SPSS V25 检索和分析数据。参与者/材料、环境、方法 该研究在伦敦一家大型体外受精中心进行。收集了 40 岁或以上接受 eSBT（第 1 组，n = 79）或 DBT（第 2 组，n = 430）的 IVF/ICSI 周期的女性的数据。之前尝试过三次以上体外受精的女性被排除在外。eSBT 被定义为单个囊胚移植，其中至少有一个可用于冷冻保存的囊胚。对接受第一个周期的患者进行亚组分析。分析了来自 511 个周期的主要结果和机会数据的作用。平均年龄为 40.6±1.2 岁。活产率为27%。第 1 组稍微年轻一些（40.2±0.6 v 40.8±1.2，p < 0.005）并且更有可能经历他们的第一个 IVF 周期（84% v 68%，p = 0.003）。第 1 组收集的卵子更多（13.6±7.3 v 11.3±5.5，p = 0.009），形成更多受精卵（8.9±4.7 v 7.3±3.6），冷冻囊胚更多（3.4±2.6 v 1.1±1.7，p <; 0005)。第 1 组中更多的女性具有高质量的囊胚（> 2 的扩大和 AA、AB、BA 或 BB 的内细胞团和滋养外胚层）转移（91% 对 71%，p < 0.005）。在对母亲年龄、之前的 IVF 周期数和囊胚质量进行逻辑回归控制后，第 1 组活产的可能性较低（aOR 0.550, 95%CI 0.306-0.988），但多胎妊娠率显着降低（0% v 24% , p = 0.024)。重要的，对于接受第一个 IVF 周期的患者 (n = 359)，在控制年龄和囊胚质量后，两组的活产率没有差异 (aOR 0.617, 95%CI 0.329-1.156)，但第 2 组的多倍数更高妊娠率 (24% v 0%, p = 0.020)。局限性，谨慎的原因 这项研究受到其回顾性的限制，使其面临信息偏倚的风险，因为它依赖于将研究变量准确记录到患者数据库中。该研究没有检查第 1 组新鲜和随后冷冻周期的累积出生率。研究结果的更广泛含义 考虑到她们的情况，女性应该就转移的囊胚数量进行个性化咨询。那些正在接受第一次试管婴儿并且有一个可供移植的囊胚的人，应该建议 DBT 与较高的多胎妊娠率相关，而总体活产率没有增加。试用注册号 不适用