Prenatal Diagnostic Testing Following High-Risk Result from Serological Screening: Which Shall We Select?

PURPOSE: We retrospectively analyzed the results of prenatal diagnosis in women with high-risk (HR) serological screening results, and discussed the reasonable application of diagnostic testing. PATIENTS AND METHODS: Diagnostic testing was done in 2239 pregnant women who had HR results from serological screening in two prenatal diagnosis centers. According to the HR results, they were divided into simple HR, HR combined with ultrasound abnormalities, and HR combined with other indication groups. After receiving counselling from clinicians, they were allowed to choose either the traditional karyotype analysis and/or chromosomal microarray analysis (CMA). RESULTS: Those who underwent CMA comprised 49.3%, 97.6%, and 100% of the HR group, HR combined with ultrasound abnormalities, and HR combined with other indication groups, respectively. Among the 100 (4.47%) clinically significant results, 55 (2.46%), 15 (0.67%), and 30 (1.34%) were chromosomal aneuploidies, chromosomal structural abnormalities, and pathogenic copy number variations (CNVs), respectively. The rate of abnormalities was 3.77%, 13.71%, and 19.05% in the simple HR, HR combined with ultrasound abnormalities, and HR combined with other indication groups, respectively. The increasing rate of clinical pathogenic CNVs was 1.34% using CMA in HR pregnant women, 9.52% in the HR combined with other indication group, and 1.24% in the simple HR group. Among the 573 women who chose both diagnostic tests, 45 had abnormal results. Only one case detected using karyotype analysis was missed on CMA. The incidence of chromosomal aneuploidy tended to increase with increase in HR values. However, chromosomal structural abnormalities and pathogenic CNVs did not increase. CONCLUSION: CMA should be recommended as the first-line diagnostic testing for women with HR screening results, especially combined with other abnormal indications.