Gu Yi-Fan, Zhou Qin-Wei, Zhang Shuo-Ping, Lu Chang-Fu, Gong Fei, Tan Yue-Qiu, Lu Guang-Xiu, Lin Ge
Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, China.
Reproductive & Genetic Hospital of CITIC-XIANGYA, Changsha, China.
PLoS One. 2018 Jan 9;13(1):e0190776. doi: 10.1371/journal.pone.0190776. eCollection 2018.
The use of assisted reproductive technology (ART) has been reported to increase the incidence of monozygotic twinning (MZT) compared with the incidence following natural conception. It has been hypothesized that splitting of the inner cell mass (ICM) through a small zona hole may result in MZT. In this study, using a cohort of patients undergoing preimplantation genetic diagnosis/screening (PGD/PGS), we compared the clinical and neonatal outcomes of human 8-shaped blastocysts hatching with ICM incarceration with partially or fully hatched blastocysts, and attempted to verify whether this phenomenon increases the incidence of MZT pregnancy or negatively impact newborns.
This retrospective study included 2059 patients undergoing PGD/PGS between March 1, 2013, and December 31, 2015. Clinical and neonatal outcomes were only collected from patients who received a single blastocyst transfer after PGD/PGS (n = 992). A 25- to 30-μm hole was made in the zona of day 3 embryos by laser. The blastocysts were biopsied and vitrified on day 6. The biopsied trophectoderm (TE) cells were analyzed using different genetic methods. One tested blastocyst was thawed and transferred to each patient in the subsequent frozen embryo transfer cycle. All the biopsied blastocysts were divided into three types: 8-shaped with ICM incarceration (type I), partially hatched without ICM incarceration (type II), and fully hatched (type III). ICM/TE grading, clinical and neonatal outcomes were compared between the groups.
The percentage of grade A ICMs in type I blastocysts (22.2%) was comparable to that in type III blastocysts (20.1%) but higher than that in type II blastocysts (4.5%). The percentage of grade A TEs in type I blastocysts (4.2%) was comparable to that in type II (3.6%) but lower than that in type III (13.5%). There were no significant differences in clinical pregnancy, MZT pregnancy, miscarriage, live birth, MZT births, and neonatal outcomes between the groups.
Compared to partially and fully hatched blastocysts, 8-shaped blastocysts with ICM incarceration showed relatively higher ICM and lower TE grades. ICM incarceration in 8-shaped blastocysts does not increase the incidence of MZT and has no negative effects on newborns in PGD/PGS patients.
据报道，与自然受孕后的发生率相比，辅助生殖技术（ART）的使用会增加单卵双胎（MZT）的发生率。有人推测，内细胞团（ICM）通过一个小的透明带孔裂开可能会导致MZT。在本研究中，我们以一组接受植入前基因诊断/筛查（PGD/PGS）的患者为研究对象，比较了人类8字形囊胚孵化且ICM嵌顿与部分或完全孵化囊胚的临床和新生儿结局，并试图验证这种现象是否会增加MZT妊娠的发生率或对新生儿产生负面影响。
这项回顾性研究纳入了2013年3月1日至2015年12月31日期间接受PGD/PGS的2059例患者。临床和新生儿结局仅收集自PGD/PGS后接受单囊胚移植的患者（n = 992）。在第3天的胚胎透明带上用激光打一个25至30μm的孔。在第6天对囊胚进行活检并玻璃化保存。对活检的滋养外胚层（TE）细胞采用不同的基因方法进行分析。在随后的冻融胚胎移植周期中，将一个经检测的囊胚解冻并移植给每位患者。所有活检的囊胚分为三种类型：8字形且ICM嵌顿（I型）、部分孵化且无ICM嵌顿（II型）和完全孵化（III型）。比较各组之间的ICM/TE分级、临床和新生儿结局。
I型囊胚中A级ICM的比例（22.2%）与III型囊胚（20.1%）相当，但高于II型囊胚（4.5%）。I型囊胚中A级TE的比例（4.2%）与II型（3.6%）相当，但低于III型（13.5%）。各组之间在临床妊娠、MZT妊娠、流产、活产、MZT出生和新生儿结局方面无显著差异。
与部分和完全孵化的囊胚相比，8字形且ICM嵌顿的囊胚显示出相对较高的ICM分级和较低的TE分级。8字形囊胚中的ICM嵌顿不会增加PGD/PGS患者中MZT的发生率，也不会对新生儿产生负面影响。
