The Centre for Reproductive & Genetic Health (CRGH), London, UK.
Hammersmith Hospital, Imperial College NHS Trust, London, UK.
Acta Obstet Gynecol Scand. 2021 Jun;100(6):1124-1131. doi: 10.1111/aogs.14088. Epub 2021 Feb 7.
The effect of embryo quality on clinical outcomes of assisted reproductive technology following a double transfer is not well defined, with some studies suggesting that a low-quality embryo transferred with a high-quality embryo decreases the live birth rate (LBR), compared with transferring a single high-quality embryo. Our study examined whether the quality of a second blastocyst transferred affects the outcome, controlling for the number of the available high-quality blastocysts (HQB).
A historical cohort study of 2346 fresh blastocyst transfers in a single fertility clinic between 2013 and 2019. The main outcomes were pregnancy, miscarriage, live birth, and multiple gestation rates. Outcomes were compared between single embryo transfers with a high-quality blastocyst (SET-H), double embryo transfers with two HQBs (DET-HH), and transfers with one high-quality and one low-quality blastocyst (DET-HL). Outcomes were also assessed between SET and DET when only low-quality blastocysts were available.
With one HQB available, DET-HL increased LBR (adjusted odds ratio [OR] 1.65, 95% CI 1.09-2.49) compared with SET-H, but increased multiple gestation rate (aOR 23.1, 95% CI 3.0-177.6). With two HQBs available, DET-HH was associated with a higher LBR (aOR 1.62, 95% CI 1.28-2.04) and lower miscarriage rate (aOR 0.56, 95% CI 0.40-0.80), but very high twin rate (aOR 49.8, 95% CI 24.3-102.1) compared with SET-H. A SET-H with at least one or more HQB available to freeze, compared with a SET-H with no other HQB available, had a higher LBR (aOR 1.69, 95% CI 1.17-2.45). When there were no HQBs available, compared with SET-L, a DET-LL had a higher live birth (aOR 3.20, 95% CI 1.78-7.703) and twin rate (aOR 3.72 × 10 ) and a lower miscarriage rate (aOR 0.24, 95% CI 0.10-0.58).
When there is one HQB available, transferring an additional low-quality blastocyst would only slightly increase the LBR, but significantly increase the twin rate, therefore SET should be recommended. When two or more HQBs are available, SET-H would have a reasonably good chance of success without the very high twin rate associated with DET-HH. DET-LL when compared with SET-L, would increase the LBR, but increase the risk of multiple gestation.
胚胎质量对辅助生殖技术双胚胎移植后临床结局的影响尚未明确，一些研究表明，与单胚胎移植相比，将质量较差的胚胎与质量较高的胚胎一起移植会降低活产率（LBR）。我们的研究通过控制可用的高质量胚胎（HQB）数量，检查了第二个囊胚的质量是否会影响结果。
这是一项对 2013 年至 2019 年间在一家生育诊所进行的 2346 例新鲜囊胚移植的回顾性队列研究。主要结局是妊娠、流产、活产和多胎妊娠率。将单胚胎移植高质量囊胚（SET-H）、双胚胎移植两个 HQB（DET-HH）和移植一个高质量和一个低质量囊胚（DET-HL）进行比较。当仅存在低质量囊胚时，还评估了 SET 与 DET 的结果。
当有一个 HQB 可用时，与 SET-H 相比，DET-HL 增加了 LBR（调整后的优势比 [OR] 1.65，95%CI 1.09-2.49），但增加了多胎妊娠率（aOR 23.1，95%CI 3.0-177.6）。当有两个 HQB 可用时，与 SET-H 相比，DET-HH 与更高的 LBR（aOR 1.62，95%CI 1.28-2.04）和更低的流产率（aOR 0.56，95%CI 0.40-0.80）相关，但双胞胎率非常高（aOR 49.8，95%CI 24.3-102.1）。与没有其他 HQB 可用的 SET-H 相比，至少有一个或更多 HQB 可用于冷冻的 SET-H 具有更高的 LBR（aOR 1.69，95%CI 1.17-2.45）。当没有 HQBs 可用时，与 SET-L 相比，DET-LL 具有更高的活产率（aOR 3.20，95%CI 1.78-7.703）和双胞胎率（aOR 3.72×10 ）和更低的流产率（aOR 0.24，95%CI 0.10-0.58）。
当有一个 HQB 可用时，转移额外的低质量囊胚只会略微增加 LBR，但会显著增加双胞胎率，因此应推荐 SET。当有两个或更多 HQB 可用时，SET-H 成功的机会相当大，而不会出现 DET-HH 相关的非常高的双胞胎率。与 SET-L 相比，DET-LL 会增加 LBR，但会增加多胎妊娠的风险。
