Cell-free nucleic acid extraction from maternal blood, DNA sequencing and analysis of sequenced regions are performed to determine the risk of specific fetal chromosomal abnormalities. The Invitae Singleton NIPS Core is validated to detect trisomies of chromosomes 13, 18 and 21 and assessment of chromosomes X and Y, in singleton pregnancies at a minimum gestational age of 10 weeks 0 days. The Invitae Singleton NIPS Expanded is validated to detect trisomies of chromosomes 13, 18, and 21; rare autosomal trisomies of chromosomes 6, 7, 8, 9, 11, 14, 15, 16, 20, and 22; assessment of chromosomes X and Y; and deletions involving specific chromosomal regions (1p36.3-p36.2, 4p16.3-p16.2, 5p15.3-p15.1, 15q11.2-q13.1 and 22q11.21) in singleton pregnancies at a minimum gestational age of 10 weeks 0 days. The Invitae Twin NIPS is validated to detect trisomies of chromosomes 13, 18 and 21 and the presence of chromosome Y for twin pregnancies at a minimum gestational age of 10 weeks 0 days. NIPS relies on the presence of fragments of cell-free placental and maternal DNA in maternal blood to assess the risk of an affected pregnancy. Many factors, both maternal (maternal blood transfusion, surgery, organ transplant, immunotherapy, neoplasm, or mosaicism) and pregnancy-related (vanishing twin, fetal demise, confined placental mosaicism, true fetal mosaicism, uniparental disomy, and polyploidy), can affect the results. NIPS is intended for screening purposes only, thus false negative and false positive results occur. This analysis does not assess the risk for other conditions, including but not limited to birth defects, open spine or ventral wall defects, intellectual disability, single gene disorders, or chromosomal abnormalities other than those listed above. The PPV and NPV calculations reported do not take into account additional clinical information such as previous screening results, positive family history or abnormal ultrasound findings. It is the duty of the healthcare provider to interpret these results in the context of the patient's clinical and family history and to recommend genetic counseling and additional testing when appropriate. This test was developed and its performance characteristics determined by Invitae. It has not been cleared or approved by the FDA.