Inner cell mass incarceration in 8-shaped blastocysts does not increase monozygotic twinning in preimplantation genetic diagnosis and screening patients

Yi-Fan Gu; Qin-Wei Zhou; Shuo-Ping Zhang; Chang-Fu Lu; Fei Gong; Yue-Qiu Tan; Guang-Xiu Lu; Ge Lin

doi:10.1371/journal.pone.0190776

Inner cell mass incarceration in 8-shaped blastocysts does not increase monozygotic twinning in preimplantation genetic diagnosis and screening patients

PLoS One. 2018 Jan 9;13(1):e0190776. doi: 10.1371/journal.pone.0190776. eCollection 2018.

Authors

Yi-Fan Gu^{1

2}, Qin-Wei Zhou¹, Shuo-Ping Zhang^{1

2}, Chang-Fu Lu^{1

2}, Fei Gong^{1

2}, Yue-Qiu Tan^{1

2}, Guang-Xiu Lu^{1

2

3

4}, Ge Lin^{1

2

3

4}

Affiliations

¹ Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, China.
² Reproductive & Genetic Hospital of CITIC-XIANGYA, Changsha, China.
³ National Engineering and Research Center of Human Stem Cell, Changsha, China.
⁴ Key Laboratory of Reproductive and Stem Cell Engineering, National Health and Family Planning Commission, Changsha, China.

Abstract

Background: 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.

Methods: 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.

Results: 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.

Conclusions: 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.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Blastocyst Inner Cell Mass*
Female
Fertilization in Vitro
Humans
Infant, Newborn
Insemination, Artificial
Pregnancy
Pregnancy Outcome
Preimplantation Diagnosis / methods*
Retrospective Studies
Twins, Monozygotic*

Grants and funding

This work was supported by the National Natural Science Foundation of China, 31401069 (http://www.nsfc.gov.cn/) and the Natural Science Foundation of Hunan Province of China, 2017JJ2327 (http://www.hnst.gov.cn/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.