1. Mc Sweeney LC, Monteith C, Kelliher N, Cody F, Tully EC, Dicker P, et al. Changing patterns of invasive fetal diagnostic testing in the era of NIPT. Am J Obstet Gynecol 2018;218:S162-3. [DOI:10.1016/j.ajog.2017.10.180]

2. Hartwig TS, Ambye L, Sørensen S, Jørgensen FS. Discordant non‐invasive prenatal testing (NIPT)-a systematic review. Prenat Diagn 2017;37:527-39. [DOI:10.1002/pd.5049]

3. Sikkema-Raddatz B, Johansson LF, De Boer EN, Boon EM, Suijkerbuijk RF, Bouman K, et al. an online tool for clinical interpretation of non-invasive prenatal testing (NIPT) results. Sci Rep 2016;6:38359. [DOI:10.1038/srep38359]

4. Norton ME, Jacobsson B, Swamy GK, Laurent LC, Ranzini AC, Brar H, et al. Cell-free DNA analysis for noninvasive examination of trisomy. New Eng J Med 2015;372:1589-97. [DOI:10.1056/NEJMoa1407349]

5. American College of Obstetricians and Gynecologists. Committee Opinion: Cell-free DNA screening for fetal aneuploidy. Sci Rep 2015. 640:1-6. [DOI:10.1097/AOG.0000000000001007]

6. Bianchi DW, Wilkins-Haug L. Integration of noninvasive DNA testing for aneuploidy into prenatal care: what has happened since the rubber met the road? Clin Chem 2014;60:78-87. [DOI:10.1373/clinchem.2013.202663]

7. Stephanie CY, Chan KA, Zheng YW, Jiang P, Liao GJ, Sun H, et al. Size-based molecular diagnostics using plasma DNA for noninvasive prenatal testing. Proc Natl Acad Sci U S A 2014;111:8583-8. [DOI:10.1073/pnas.1406103111]

8. Song K, Musci TJ, Caughey AB. Clinical utility and cost of non-invasive prenatal testing with cfDNA analysis in high-risk women based on a US population. J Matern Fetal Neonatal Med 2013;26:1180-5. [DOI:10.3109/14767058.2013.770464]

9. Wald NJ, Lau KW, Bestwick JP, Old RW, Huttly WJ, Cheng R. Specifying a Gold Standard for the Validation of Fetal Fraction Estimation in Prenatal Screening. Clin Chem 2018;64:1394-9. [DOI:10.1373/clinchem.2018.288670]

10. Oepkes D, Page‐Christiaens GC, Bax CJ, Bekker MN, Bilardo CM, Boon EM, et al. Trial by Dutch laboratories for evaluation of non‐invasive prenatal testing. Part I-clinical impact. Prenat Diagn 2016;36:1083-90. [DOI:10.1002/pd.4945]

11. Dey M, Sharma S, Aggarwal S. Prenatal screening methods for aneuploidies. North Am J Med Sci 2013;5:182. [DOI:10.4103/1947-2714.109180]

12. Flöck A, Tu NC, Rüland A, Holzgreve W, Gembruch U, Geipel A. Non-invasive prenatal testing (NIPT): Europe's first multicenter post-market clinical follow-up study validating the quality in clinical routine. Arch Gynecol Obstet 2017;296:923-8. [DOI:10.1007/s00404-017-4517-3]

13. Jiang T, Ding J, Zhang XQ, Zhang XJ, Zhang B, Wang T, et al. Analysis of Down syndrome failed to be diagnosed after prenatal screening: A multicenter study. Medicine 2017;96. [DOI:10.1097/MD.0000000000007166]

14. Papageorghiou AT, Khalil A, Forman M, Hulme R, Mazey R, Mousa HA, et al. Clinical evaluation of the IONA test: a non‐invasive prenatal screening test for trisomies 21, 18 and 13. Ultrasound Obstet Gynecol 2016;47:188-93. [DOI:10.1002/uog.15791]

15. Gil MM, Quezada MS, Bregant B, Ferraro M, Nicolaides KH. Implementation of maternal blood cell‐free DNA testing in early screening for aneuploidies. Ultrasound Obstet Gynecol 2013;42:34-40. [DOI:10.1002/uog.12504]

16. Liao GJ, Gronowski AM, Zhao Z. Non-invasive prenatal testing using cell-free fetal DNA in maternal circulation. Clinica Chimica Acta 2014 ;428:44-50. [DOI:10.1016/j.cca.2013.10.007]