背景:母亲使用抗凝药物可能会增加基于无细胞DNA筛查的不确定结果率,但是现有的研究被包括患有自身免疫性疾病的个体所混淆,单独与不确定的结果有关。其他人提出染色体水平Z分数的变化是不确定结果的原因,但其病因尚不确定。
目的:本研究旨在评估胎儿分数的差异,不确定的结果率,与接受非侵入性产前筛查的对照组相比,无自身免疫性疾病抗凝个体的总无细胞DNA浓度。其次,使用嵌套的大小写控件设计,我们评估了片段大小的差异,GC含量,和Z分数来评估实验室水平的测试特征。
方法:这是一项回顾性的单机构研究,研究对象是在2017年至2021年间使用低通全基因组测序进行基于无细胞DNA的无创产前筛查的孕妇。患有自身免疫性疾病的人,怀疑非整倍体,未报告胎儿分数的病例被排除.抗凝包括肝素衍生产品(普通肝素,低分子量肝素),氯吡格雷,和磺达肝素,单独服用阿司匹林的人有一个单独的小组。不确定的结果被定义为胎儿分数<4%。我们评估了母体抗凝和阿司匹林使用之间的关联,和胎儿分数,不确定的结果,和使用单变量和多变量分析的总无细胞DNA浓度,控制体重指数,样本采集时的胎龄,和胎儿性。对于抗凝队列,我们比较了病例(抗凝治疗)和部分对照组的实验室水平检测特征.最后,我们评估了有或没有不确定结果的抗凝治疗者之间染色体水平Z评分的差异.
结果:共有1707名孕妇符合纳入标准。其中,29例接受抗凝治疗,81例仅接受阿司匹林治疗。对于那些接受抗凝治疗的人,胎儿分数显著降低(9.3%vs11.7%;P<0.01),结果不确定率明显更高(17.2%vs2.7%;P<.001),并且总的无细胞DNA浓度显著高于(218pg/μL比83.7pg/μL;P<.001)。在那些单独服用阿司匹林的人中,胎儿分数较低(10.6%vs11.8%;P=.04);然而,不确定结果的比率(3.7%vs2.7%;P=.57)或总无细胞DNA浓度(90.1pg/μLvs83.8pg/μL;P=.31)没有差异。控制孕妇体重指数后,样本采集时的胎龄,和胎儿性别,抗凝与不确定结果的可能性增加>8倍相关(调整后的优势比,8.7;95%置信区间,3.1-24.9;P<.001),但不是阿司匹林(调整后的赔率比,1.2;95%置信区间,0.3-4.1;P=.8)。抗凝与无细胞DNA片段大小或GC含量的明显差异无关。尽管观察到13号染色体Z评分存在差异,18号或21号染色体均未观察到,并且这种差异不会导致不确定的结果。
结论:在没有自身免疫性疾病的情况下,抗凝使用,但不是阿司匹林,与较低的胎儿分数有关,总的无细胞DNA浓度更高,以及更高的不确定结果率。抗凝使用不伴有无细胞DNA片段大小或GC含量的差异。染色体水平Z评分的统计学差异在临床上不影响非整倍性检测。这表明抗凝对基于无细胞DNA的非侵入性产前筛查检测的稀释作用可能导致低胎儿分数和不确定的结果。而不是实验室或测序水平的变化。
Maternal anticoagulation use may increase indeterminate result rates on cell-free DNA-based screening, but existing studies are confounded by inclusion of individuals with autoimmune disease, which alone is associated with indeterminate results. Changes in chromosome level Z-scores are proposed by others as a reason for indeterminate results, but the etiology of this is uncertain.
This study aimed to evaluate differences in fetal fraction, indeterminate result rate, and total cell-free DNA concentration in individuals on anticoagulation without autoimmune disease compared with controls undergoing noninvasive prenatal screening. Secondly, using a nested case-control design, we evaluated differences in fragment size, GC-content, and Z-scores to evaluate laboratory-level test characteristics.
This was a retrospective single-institution study of pregnant individuals undergoing cell-free DNA-based noninvasive prenatal screening using low-pass whole-genome sequencing between 2017 and 2021. Individuals with autoimmune disease, suspected aneuploidy, and cases where fetal fraction was not reported were excluded. Anticoagulation included heparin-derived products (unfractionated heparin, low-molecular-weight heparin), clopidogrel, and fondaparinux, with a separate group for those on aspirin alone. An indeterminate result was defined as fetal fraction <4%. We evaluated the association between maternal anticoagulation or aspirin use, and fetal fraction, indeterminate results, and total cell-free DNA concentration using univariate and multivariate analyses, controlling for body mass index, gestational age at sample collection, and fetal sex. For the anticoagulation cohort, we compared laboratory-level test characteristics among cases (on anticoagulation) and a subset of controls. Lastly, we evaluated for differences in chromosome level Z-scores among those on anticoagulation with and without indeterminate results.
A total of 1707 pregnant individuals met the inclusion criteria. Of those, 29 were on anticoagulation and 81 were on aspirin alone. For those on anticoagulation, the fetal fraction was significantly lower (9.3% vs 11.7%; P<.01), the indeterminate result rate was significantly higher (17.2% vs 2.7%; P<.001), and the total cell-free DNA concentration was significantly higher (218 pg/μL vs 83.7 pg/μL; P<.001). Among those on aspirin alone, the fetal fraction was lower (10.6% vs 11.8%; P=.04); however, there were no differences in the rate of indeterminate results (3.7% vs 2.7%; P=.57) or total cell-free DNA concentration (90.1 pg/μL vs 83.8 pg/μL; P=.31). After controlling for maternal body mass index, gestational age at sample collection, and fetal sex, anticoagulation was associated with an >8-fold increase in the likelihood of an indeterminate result (adjusted odds ratio, 8.7; 95% confidence interval, 3.1-24.9; P<.001), but not aspirin (adjusted odds ratio, 1.2; 95% confidence interval, 0.3-4.1; P=.8). Anticoagulation was not associated with appreciable differences in cell-free DNA fragment size or GC-content. Although differences in chromosome 13 Z-scores were observed, none were observed for chromosomes 18 or 21, and this difference did not contribute to the indeterminate result call.
In the absence of autoimmune disease, anticoagulation use, but not aspirin, is associated with lower fetal fraction, higher total cell-free DNA concentration, and higher rates of indeterminate results. Anticoagulation use was not accompanied by differences in cell-free DNA fragment size or GC-content. Statistical differences in chromosome level Z-scores did not clinically affect aneuploidy detection. This suggests a likely dilutional effect by anticoagulation on cell-free DNA-based noninvasive prenatal screening assays contributing to low fetal fraction and indeterminate results, and not laboratory or sequencing-level changes.