Abstract：
UNASSIGNED: Noninvasive prenatal testing (NIPT) is the most common method for prenatal aneuploidy screening. Low fetal fraction (LFF) is the primary reason for NIPT failure. Consequently, factors associated with LFF should be elucidated for optimal clinical implementation of NIPT.
UNASSIGNED: In this study, NIPT data from January 2019 to December 2022 from the laboratory records and obstetrical and neonatal data from the electronic medical records were collected and analyzed. Subjects with FF >3.50% were assigned to the control group, subjects with FF <3.50% once were assigned to the LFF group, and subjects with FF <3.50% twice were assigned to the repetitive low fetal fraction (RLFF) group. Factors, including body mass index (BMI), gestational age, maternal age, twin pregnancy, and in vitro fertilization (IVF) known to be associated with LFF were assessed by Kruskal-Wallis H test and logistic regression. Clinical data on first trimester pregnancy-associated plasma protein-A (PAPP-A), beta-human chorionic gonadotropin (β-hCG), gestational age at delivery, birth weight at delivery, and maternal diseases were obtained from the hospital\'s prenatal and neonatal screening systems (twin pregnancy was not included in the data on gestational age at delivery and the control group did not include data on maternal diseases.), and were analyzed using Kruskal-Wallis H test and Chi-square test.
UNASSIGNED: Among the total of 63,883 subjects, 63,605 subjects were assigned to the control group, 197 subjects were assigned to the LFF group, and 81 subjects were assigned to the RLFF group. The median of BMI in the three groups was 22.43 kg/m2 (control), 25.71 kg/m2 (LFF), and 24.54 kg/m2 (RLFF). The median gestational age in the three groups was 130 days (control), 126 days (LFF), and 122/133 days (RLFF). The median maternal age in the three groups was 29 (control), 29 (LFF), and 33-years-old (RLFF). The proportion of twin pregnancies in the three groups was 3.3% (control), 10.7% (LFF), and 11.7% (RLFF). The proportion of IVF in the three groups was 4.7% (control), 11.7% (LFF), and 21.3% (RLFF). The factors significantly associated with LFF included BMI [2.18, (1.94, 2.45), p < 0.0001], gestational age [0.76, (0.67, 0.87), p < 0.0001], twin pregnancy [1.62, (1.02, 2.52), p = 0.0353], and IVF [2.68, (1.82, 3.86), p < 0.0001]. The factors associated with RLFF included maternal age [1.54, (1.17, 2.05), p = 0.0023] and IVF [2.55, (1.19, 5.54), p = 0.016]. Multiples of the median (MOM) value of β-hCG and pregnant persons\' gestational age at delivery were significantly decreased in the LFF and RLFF groups compared to the control group.
UNASSIGNED: According to our findings based on the OR value, factors associated strongly with LFF include a high BMI and the use of IVF. Factors associated less strongly with LFF include early gestational age and twin pregnancy, while advanced maternal age and IVF were independent risk factors for a second LFF result.
Body mass index, gestational age, maternal age, twin pregnancy, and in vitro fertilization are associated with fetal fraction. We added the repetitive low fetal fraction population and used a large normal population as a control to identify the main factors associated with low fetal fraction.
UNASSIGNED: In this study, NIPT data from January 2019 to December 2022 from the laboratory records and obstetrical and neonatal data from the electronic medical records were collected and analyzed. Subjects with FF >3.50% were assigned to the control group, subjects with FF <3.50% once were assigned to the LFF group, and subjects with FF <3.50% twice were assigned to the repetitive low fetal fraction (RLFF) group. Factors, including body mass index (BMI), gestational age, maternal age, twin pregnancy, and in vitro fertilization (IVF) known to be associated with LFF were assessed by Kruskal-Wallis H test and logistic regression. Clinical data on first trimester pregnancy-associated plasma protein-A (PAPP-A), beta-human chorionic gonadotropin (β-hCG), gestational age at delivery, birth weight at delivery, and maternal diseases were obtained from the hospital\'s prenatal and neonatal screening systems (twin pregnancy was not included in the data on gestational age at delivery and the control group did not include data on maternal diseases.), and were analyzed using Kruskal-Wallis H test and Chi-square test.
UNASSIGNED: Among the total of 63,883 subjects, 63,605 subjects were assigned to the control group, 197 subjects were assigned to the LFF group, and 81 subjects were assigned to the RLFF group. The median of BMI in the three groups was 22.43 kg/m2 (control), 25.71 kg/m2 (LFF), and 24.54 kg/m2 (RLFF). The median gestational age in the three groups was 130 days (control), 126 days (LFF), and 122/133 days (RLFF). The median maternal age in the three groups was 29 (control), 29 (LFF), and 33-years-old (RLFF). The proportion of twin pregnancies in the three groups was 3.3% (control), 10.7% (LFF), and 11.7% (RLFF). The proportion of IVF in the three groups was 4.7% (control), 11.7% (LFF), and 21.3% (RLFF). The factors significantly associated with LFF included BMI [2.18, (1.94, 2.45), p < 0.0001], gestational age [0.76, (0.67, 0.87), p < 0.0001], twin pregnancy [1.62, (1.02, 2.52), p = 0.0353], and IVF [2.68, (1.82, 3.86), p < 0.0001]. The factors associated with RLFF included maternal age [1.54, (1.17, 2.05), p = 0.0023] and IVF [2.55, (1.19, 5.54), p = 0.016]. Multiples of the median (MOM) value of β-hCG and pregnant persons\' gestational age at delivery were significantly decreased in the LFF and RLFF groups compared to the control group.
UNASSIGNED: According to our findings based on the OR value, factors associated strongly with LFF include a high BMI and the use of IVF. Factors associated less strongly with LFF include early gestational age and twin pregnancy, while advanced maternal age and IVF were independent risk factors for a second LFF result.
Body mass index, gestational age, maternal age, twin pregnancy, and in vitro fertilization are associated with fetal fraction. We added the repetitive low fetal fraction population and used a large normal population as a control to identify the main factors associated with low fetal fraction.
摘要：
■非侵入性产前检测（NIPT）是产前非整倍体筛查的最常用方法。低胎儿分数(LFF)是NIPT失败的主要原因。因此,应阐明与LFF相关的因素，以优化NIPT的临床实施。
■在这项研究中，收集并分析了2019年1月至2022年12月来自实验室记录的NIPT数据以及来自电子病历的产科和新生儿数据。FF>3.50%的受试者被分配到对照组,FF<3.50%的受试者一旦被分配到LFF组,并且两次FF<3.50％的受试者被分配到重复低胎儿分数（RLFF）组。因素，包括体重指数（BMI），胎龄,产妇年龄,双胎妊娠,通过Kruskal-WallisH检验和逻辑回归评估已知与LFF相关的体外受精（IVF）。孕早期妊娠相关血浆蛋白-A（PAPP-A）的临床数据，β-人绒毛膜促性腺激素（β-hCG），分娩时的胎龄，分娩时的出生体重，孕产妇疾病来自医院的产前和新生儿筛查系统(双胎妊娠未包括在分娩时的孕龄数据中,对照组未包括孕产妇疾病数据.),并采用Kruskal-WallisH检验和卡方检验进行分析。
■在总共63,883个科目中，63,605名受试者被分配到对照组，197名受试者被分配到LFF组，81名受试者被分配到RLFF组。三组的BMI中位数为22.43kg/m2(对照组),25.71kg/m2(LFF),和24.54kg/m2（RLFF）。三组的中位胎龄为130天(对照组),126天（LFF），和122/133天（RLFF）。三组产妇年龄中位数为29岁(对照组),29(LFF),33岁（RLFF）。三组双胎妊娠比例为3.3%(对照组),10.7%（LFF），和11.7%（RLFF）。三组的IVF比例为4.7%(对照组),11.7%（LFF），和21.3%（RLFF）。与LFF显著相关的因素包括BMI[2.18，（1.94，2.45），p<0.0001],胎龄[0.76，（0.67，0.87），p<0.0001],双胎妊娠[1.62,(1.02,2.52),p=0.0353],和体外受精[2.68，（1.82，3.86），p<0.0001]。与RLFF相关的因素包括产妇年龄[1.54，（1.17，2.05），p=0.0023]和IVF[2.55，（1.19，5.54），p=0.016]。与对照组相比，LFF和RLFF组的β-hCG和孕妇分娩时胎龄的中位数（MOM）倍数显着降低。
■根据我们基于OR值的发现，与LFF密切相关的因素包括高BMI和使用IVF。与LFF相关程度较低的因素包括胎龄早期和双胎妊娠。而高龄产妇和IVF是第二次LFF结果的独立危险因素。
身体质量指数,胎龄,产妇年龄,双胎妊娠,体外受精与胎儿分数有关。我们添加了重复的低胎儿分数人群，并使用大量正常人群作为对照，以确定与低胎儿分数相关的主要因素。
■在这项研究中，收集并分析了2019年1月至2022年12月来自实验室记录的NIPT数据以及来自电子病历的产科和新生儿数据。FF>3.50%的受试者被分配到对照组,FF<3.50%的受试者一旦被分配到LFF组,并且两次FF<3.50％的受试者被分配到重复低胎儿分数（RLFF）组。因素，包括体重指数（BMI），胎龄,产妇年龄,双胎妊娠,通过Kruskal-WallisH检验和逻辑回归评估已知与LFF相关的体外受精（IVF）。孕早期妊娠相关血浆蛋白-A（PAPP-A）的临床数据，β-人绒毛膜促性腺激素（β-hCG），分娩时的胎龄，分娩时的出生体重，孕产妇疾病来自医院的产前和新生儿筛查系统(双胎妊娠未包括在分娩时的孕龄数据中,对照组未包括孕产妇疾病数据.),并采用Kruskal-WallisH检验和卡方检验进行分析。
■在总共63,883个科目中，63,605名受试者被分配到对照组，197名受试者被分配到LFF组，81名受试者被分配到RLFF组。三组的BMI中位数为22.43kg/m2(对照组),25.71kg/m2(LFF),和24.54kg/m2（RLFF）。三组的中位胎龄为130天(对照组),126天（LFF），和122/133天（RLFF）。三组产妇年龄中位数为29岁(对照组),29(LFF),33岁（RLFF）。三组双胎妊娠比例为3.3%(对照组),10.7%（LFF），和11.7%（RLFF）。三组的IVF比例为4.7%(对照组),11.7%（LFF），和21.3%（RLFF）。与LFF显著相关的因素包括BMI[2.18，（1.94，2.45），p<0.0001],胎龄[0.76，（0.67，0.87），p<0.0001],双胎妊娠[1.62,(1.02,2.52),p=0.0353],和体外受精[2.68，（1.82，3.86），p<0.0001]。与RLFF相关的因素包括产妇年龄[1.54，（1.17，2.05），p=0.0023]和IVF[2.55，（1.19，5.54），p=0.016]。与对照组相比，LFF和RLFF组的β-hCG和孕妇分娩时胎龄的中位数（MOM）倍数显着降低。
■根据我们基于OR值的发现，与LFF密切相关的因素包括高BMI和使用IVF。与LFF相关程度较低的因素包括胎龄早期和双胎妊娠。而高龄产妇和IVF是第二次LFF结果的独立危险因素。
身体质量指数,胎龄,产妇年龄,双胎妊娠,体外受精与胎儿分数有关。我们添加了重复的低胎儿分数人群，并使用大量正常人群作为对照，以确定与低胎儿分数相关的主要因素。
