UOS Physiopathology of Human Reproduction, IRCCS Ospedale Policlinico San Martino, Largo R. Benzi, 10, 16132, Genova, Italy.
Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), Academic Unit of Obstetrics and Gynecology, University of Genova, Genova, Italy.
BMC Pregnancy Childbirth. 2021 May 5;21(1):361. doi: 10.1186/s12884-021-03820-7.
In assisted reproduction technology embryo competence is routinely evaluated on morphological criteria but efficacy remains relatively low. Additional information could be obtained by evaluating pronuclear (PN) morphology. Up to now controversial results have been reported about the prognostic value of PN score. One of the main limitations of literature data is the use of different PN classification methods. In this regard, in 2011 the ESHRE and Alpha Scientists in Reproductive Medicine defined three PN categories to standardize zygote assessment. In this study we evaluated whether the consensus ESHRE-Alpha system for the pronuclear scoring could be an useful additional criterion to improve prediction of embryo implantation potential.
This is a retrospective, longitudinal, observational, cohort study. We included 3004 zygotes from 555 women who underwent ICSI treatment at our Center between January 2014 and June 2019. The PN were categorized as score 1: symmetrical, 2: non-symmetrical, 3: abnormal. A subset of 110 zygotes did not cleaved. On day 2-3 1163 embryos were transferred, 232 arrested, and 9 were cryopreserved. Among the 1490 embryos cultured up to day 5-7, 516 became blastocysts: 123 were transferred on day 5 and 393 were cryopreserved. Comparisons of age, cleavage and blastocyst rate, quality of embryos, implantation success among PN score groups were evaluated by chi-square test or Kruskal-Wallis test as appropriate. Potential predictors of embryo implantation were first tested in univariable analysis using generalized estimating equations taking into account correlation between embryos originated from the same patient. Then, variables potentially associated with implantation success (P<0.05) were included in a multivariable analysis for calculating the adjusted odds ratio (OR) and 95% confidence interval (CI).
There was no significant difference in patients'age, cleavage and blastulation rates, and embryo morphology among the three PNscore groups. The PN score 1-embryos had a greater implantation success respect to score 2-3-ones (OR 1.83; 95% CI 1.34-2.50, P=0.0001). Consistently, the pronuclear score remained predictive of implantation in top quality embryos (OR 1.68; 95%CI 1.17-2.42, P= 0.005).
The consensus pronuclear score may be routinely included among criteria for embryo evaluation to increase patients' chance of becoming pregnant.
在辅助生殖技术中，胚胎的活力通常通过形态学标准进行评估，但效果仍然相对较低。通过评估原核（PN）形态，可以获得更多信息。到目前为止，关于 PN 评分的预后价值，已有报道结果存在争议。文献数据的主要局限性之一是使用不同的 PN 分类方法。在这方面，2011 年，ESHRE 和生殖医学阿尔法科学家定义了三个 PN 类别，以规范胚胎评估。在这项研究中，我们评估了共识 ESHRE-Alpha 系统用于原核评分是否可以作为提高胚胎着床潜能预测的有用附加标准。
这是一项回顾性、纵向、观察性队列研究。我们纳入了 2014 年 1 月至 2019 年 6 月在我们中心接受 ICSI 治疗的 555 名女性的 3004 个受精卵。PN 被分为 1 分：对称；2 分：不对称；3 分：异常。110 个未分裂的受精卵为一组。在第 2-3 天，有 1163 个胚胎被移植，232 个胚胎停滞，9 个胚胎被冷冻。在培养至第 5-7 天的 1490 个胚胎中，有 516 个发育成囊胚：5 个胚胎在第 5 天被移植，393 个胚胎被冷冻。对不同 PN 评分组的年龄、分裂和囊胚形成率、胚胎质量、着床成功率进行比较，采用卡方检验或 Kruskal-Wallis 检验，如有必要。采用广义估计方程，考虑到来自同一患者的胚胎之间的相关性，首先在单变量分析中测试胚胎着床的潜在预测因子。然后，将与着床成功率相关的潜在变量（P<0.05）纳入多变量分析，计算调整后的优势比（OR）和 95%置信区间（CI）。
在三组 PN 评分中，患者年龄、分裂和囊胚形成率以及胚胎形态均无显著差异。PN 评分 1 组胚胎的着床成功率高于评分 2-3 组（OR 1.83；95%CI 1.34-2.50，P=0.0001）。同样，原核评分在优质胚胎中仍然具有预测着床的能力（OR 1.68；95%CI 1.17-2.42，P=0.005）。
共识原核评分可常规纳入胚胎评估标准，以增加患者妊娠机会。
