To explore the application of single nucleotide polymorphism array (SNP-array) technology in prenatal diagnosis of fetal lateral ventriculomegaly.

From January 2016 to October 2018, 433 pregnant women with fetal lateral ventriculomegaly in the second and third trimester were selected as research subjects. The age ranged from 19 to 45 years old, and gestational age ranged from 16^{+ 6} to 37^{+ 6} weeks. Among them, 135 cases (31.2%) were in the second trimester and 298 cases (68.8%) in the third trimester. The fetal karyotype analysis results and SNP-array detection results of 433 pregnant women were analyzed retrospectively. This study was approved by the ethics committee of Maternal & Child Health Hospital of Guangxi Zhuang Autonomous Region [No. 2019 (3-21)]. Informed consent was obtained from each participate.

①Among the 135 pregnant women in the second trimester who underwent amniocentesis for prenatal diagnosis, 22 cases of fetal chromosomal karyotypic abnormalities were detected, with an abnormality detection rate of 16.3% (22/135). And 17 cases of fetal chromosomal karyotypic abnormalities were detected in 298 pregnant women in the third trimester undergoing routine umbilical venipuncture, with an abnormality detection rate of 5.7% (17/298). ② Among 135 amniotic fluid samples of pregnant women in the second trimester, 28 cases of fetal chromosomal abnormalities were detected by SNP-array, with an abnormality detection rate of 20.7% (28/135). Among the 298 cord blood samples of pregnant women in the third trimester, 37 cases of fetal chromosomal abnormalities were detected by SNP-array, with an abnormality detection rate of 12.4% (37/298). Among the 65 cases of abnormal results of SNP-array detection, 39 cases (60.0%) were abnormal with fetal karyotype analysis, and 26 cases (40.0%) were with normal fetal karyotype analysis results. Among the 26 cases with normal fetal karyotype analysis results while with abnormal SNP-array detection results, fetuses of 11 cases were pathogenic copy number variations (CNVs) (7 cases with chromosomal microdeletion, 1 case with chromosomal microduplication, and 3 cases with chromosomal microdeletion combined with microduplication); 1 case was suspected pathogenic CNVs (chromosomal microdeletion); 14 cases with unknown clinical significance of CNVs (5 cases with chromosome microdeletion, 4 cases with chromosome microdeletion, 5 cases with loss of heterozygosity between one or more chromosomes).

Among pregnant women with fetal lateral ventriculomegaly in the second and third trimester, SNP-array detection is helpful to find fetal abnormal chromosome submicroscopic structure which cannot be detected by fetal karyotype analysis.