Supplementary Material for: Incidence and Types of Fetal Chromosomal Abnormalities in First Trimester of Thai Pregnant Women between Miscarriages and Intrauterine Survivals

Abortion is a common pregnancy complication. Fetuses with several types of chromosomal abnormalities are aborted during the first trimester, while others have a better chance of surviving. This research aims to study and compare the incidence and types of fetal chromosomal abnormalities during the first trimester of Thai pregnant women between miscarriages and intrauterine survivals. Cytogenetic and BACs-on-Beads™ assays were assessed from 2010 to 2020 in Ramathibodi Hospital using first trimester samples of 265 chorionic villi as a retrospective study. Chromosomal abnormalities were observed in 135 cases (50.94%) including 38.11% miscarriages and 12.83% intrauterine survivals. In total, 75.56% single autosomal trisomies, 18.52% sex chromosome aneuploidies, 5.19% double aneuploidies, and 0.74% structural abnormalities were detected. In miscarriages, all chromosomes were involved in abnormalities except chromosomes 1, 5, 8, 9, 11, and 17, while survivals had only trisomy 13, 18, 21, and sex chromosome aneuploidy. Trisomy 16 and 18 were the most common abnormalities in miscarriages and intrauterine survivals, respectively. The highest rate of chromosomal aberrations was demonstrated in 8–9+6 and 12–13+6 weeks of gestation in miscarriages and intrauterine survivals, respectively. Correlation between chromosomal abnormalities and maternal age <35 years and ≥35 years was significant (p < 0.05) in intrauterine survival and first trimester groups.

流产是妊娠常见并发症。多种染色体异常的胎儿会在妊娠早期流产，而部分胎儿则可获得更高的存活几率。本研究旨在探讨并对比泰国妊娠早期孕妇中，流产组与宫内存活组胎儿染色体异常的发生率及类型分布。本研究为回顾性研究，纳入2010年至2020年泰国拉玛提巴迪医院（Ramathibodi Hospital）收集的265例妊娠早期绒毛膜绒毛样本，对其行细胞遗传学（cytogenetic）检测与微球BAC技术（BACs-on-Beads™）分析。共135例（50.94%）检出染色体异常，其中流产组占38.11%，宫内存活组占12.83%。检出的异常类型中，单常染色体三体占75.56%，性染色体非整倍体占18.52%，双非整倍体占5.19%，染色体结构异常占0.74%。流产组的染色体异常涉及除1号、5号、8号、9号、11号及17号染色体外的所有染色体，而宫内存活组仅检出13三体、18三体、21三体及性染色体非整倍体。流产组最常见的染色体异常为16三体，宫内存活组最常见的则为18三体。流产组与宫内存活组的染色体异常检出率峰值分别出现在妊娠8~9+6周与12~13+6周。在宫内存活组及妊娠早期队列中，染色体异常与产妇年龄<35岁、≥35岁的相关性均具有统计学意义（p<0.05）。