Department of Obstetrics and Gynecology, The Jikei University School of Medicine, Tokyo, Japan.
Center for Maternal-Fetal, Neonatal and Reproductive Medicine, National Center for Child Health and Development, Tokyo, Japan.
J Hum Genet. 2022 May;67(5):261-265. doi: 10.1038/s10038-021-01001-0. Epub 2022 Jan 1.
The incidence of chromosomal abnormalities in twin pregnancies is not well-studied. In this retrospective study, we investigated the frequency of chromosomal abnormalities in twin pregnancies and compared the incidence of chromosomal abnormalities in dichorionic diamniotic (DD) and monochorionic diamniotic (MD) twins. We used data from 57 clinical facilities across Japan. Twin pregnancies of more than 12 weeks of gestation managed between January 2016 and December 2018 were included in the study. A total of 2899 and 1908 cases of DD and MD twins, respectively, were reported, and the incidence of chromosomal abnormalities in one or both fetuses was 0.9% (25/2899) and 0.2% (4/1908) in each group (p = 0.004). In this study, the most common chromosomal abnormality was trisomy 21 (51.7% [15/29]), followed by trisomy 18 (13.8% [4/29]) and trisomy 13 (6.9% [2/29]). The incidence of trisomy 21 in MD twins was lower than that in DD twins (0.05% vs. 0.5%, p = 0.007). Trisomy 21 was less common in MD twins, even when compared with the expected incidence in singletons (0.05% vs. 0.3%, RR 0.15 [95% CI 0.04-0.68]). The risk of chromosomal abnormality decreases in twin pregnancies, especially in MD twins.
双胎妊娠中染色体异常的发生率尚未得到充分研究。在这项回顾性研究中，我们调查了双胎妊娠中染色体异常的频率，并比较了双绒毛膜双羊膜囊（DCDA）和单绒毛膜双羊膜囊（MCDA）双胎的染色体异常发生率。我们使用了来自日本 57 个临床机构的数据。研究纳入了 2016 年 1 月至 2018 年 12 月期间妊娠 12 周以上的双胎妊娠。分别报告了 2899 例和 1908 例 DCDA 和 MCDA 双胎，一组中一个或两个胎儿的染色体异常发生率分别为 0.9%（25/2899）和 0.2%（4/1908）（p=0.004）。在这项研究中，最常见的染色体异常是 21 三体（51.7%[15/29]），其次是 18 三体（13.8%[4/29]）和 13 三体（6.9%[2/29]）。MCDA 双胎的 21 三体发生率低于 DCDA 双胎（0.05%比 0.5%，p=0.007）。即使与单胎妊娠的预期发生率（0.05%比 0.3%，RR 0.15[95%CI 0.04-0.68]）相比，MCDA 双胎的 21 三体也较少见。双胎妊娠中染色体异常的风险降低，尤其是在 MCDA 双胎中。
