Definitive diagnosis of Down syndrome and other chromosomal abnormalities requires amniocentesis or chorionic villus sampling (CVS), both of which are invasive procedures that carry a risk of miscarriage estimated at 0.5% to 1%. Less invasive screening programs have been developed with the use of biochemical markers that show an association with Down syndrome.
The May 2016 American College of Obstetricians and Gynecologists recommendation for first trimester screening for fetal abnormalities includes a nuchal translucency (ultrasound detection of subcutaneous edema in the fetal neck), serum free beta subunit of human chorionic gonadotropin (β-hCG) and pregnancy-associated plasma protein-A (PAPP-A). A specific risk estimate is calculated using these results as well as maternal factors such as maternal age, prior history, weight, race, and number of fetuses. Combined screening shows an 82% to 87% predictability rating when done in the first trimester. Measurement of nuchal translucency alone is less effective for first-trimester screening than the combined testing.
Another potential ultrasound marker is fetal nasal bone examination. The technique for assessing the nasal bone using ultrasound involves viewing the fetal face longitudinally and exactly in the midline. The nasal bones are considered to be present if the line within the bridge of the nose is more echogenic than the overlying skin and absent if the echogenicity is the same or less than the skin, or if it is not visible. The absence of fetal nasal bone is considered to be a positive test result, indicating an increased risk of Down syndrome.
First-trimester screening for detection of Down syndrome incorporating maternal serum markers and measurement of fetal nuchal translucency may be considered medically necessary if the medical appropriateness criteria are met. (See Medical Appropriateness below.)
First-trimester screening for detection of Down syndrome using measurement of nuchal translucency alone is considered investigational.
First-trimester screening for detection of Down syndrome using fetal nasal bone assessment translucency is considered investigational.
First-trimester screening for detection of Down syndrome is considered medically appropriate if ALL of the following are met:
Screening includes the maternal serum markers free beta subunit of human chorionic gonadotropin (β-hCG) and pregnancy-associated plasma protein-A (PAPP-A)
Screening includes measurement of fetal nuchal translucency
Nuchal translucency (NT) is performed between 10 weeks 0 days and 13 weeks 6 days of gestation
Individual desires information regarding risk of Down Syndrome
Individual has been adequately counseled
Any specific products referenced in this policy are just examples and are intended for illustrative purposes only. It is not intended to be a recommendation of one product over another, and is not intended to represent a complete listing of all products available. These examples are contained in the parenthetical e.g. statement.
We develop Medical Policies to provide guidance to Members and Providers. This Medical Policy relates only to the services or supplies described in it. The existence of a Medical Policy is not an authorization, certification, explanation of benefits, or a contract for the service (or supply) that is referenced in the Medical Policy. For a determination of the benefits that a Member is entitled to receive under his or her health plan, the Member's health plan must be reviewed. If there is a conflict between the Medical Policy and a health plan, the express terms of the health plan will govern.
This policy does not address the second trimester maternal markers which measure alpha-fetoprotein, human chorionic gonadotropin and unconjugated estriol (i.e., triple screen) or the addition of a fourth marker, inhibin-A (quadruple screen).
There is insufficient evidence on the performance of fetal nasal bone assessment to determine its impact on health outcomes. Additional studies are needed before conclusions can be drawn about its utility.
American College of Obstetricians and Gynecologists, Committee on Genetics; Society of Maternal-Fetal Medicine. (2015, September). Cell-free DNA Screening for fetal aneuploidy. committee opinion number 640. Retrieved August 7, 2015 from: http://www.acog.org.
American College of Obstetricians and Gynecologists. ACOG Practice Bulletin Number 162. (2016, May) Prenatal diagnostic testing for genetic disorders. Retrieved November 22, 2016 from: http://www.acog.org/Resources-And-Publications/Practice-Bulletins-List.
American College of Obstetricians and Gynecologists. ACOG Practice Bulletin Number 163. (2016, May) Screening for fetal aneuploidy. Retrieved November 22, 2016 from: http://www.acog.org/Resources-And-Publications/Practice-Bulletins-List.
Hsiao, C., Cheng, P., Shaw, S., Hsu, J., Chen, R., Tseng, Y., et. al. (2014) Extended first-trimester screening using multiple sonographic markers and maternal serum biochemistry: a five-year prospective study. Fetal Diagnostic Theory. 2014;35(4):296-301. Abstract retrieved November 22, 2016 from PubMed database.
Kagan, K. O., Staboulidou, I., Cruz, J., Wright, D., & Nicolaides, K. H. (2010). Two-stage first-trimester screening for trisomy 21 by ultrasound assessment and biochemical testing. Ultrasound in Obstetrics & Gynecology, 36 (5), 542-547. (Level 3 evidence)
Kim, S., & Jun, J. (2013). Simplified protocol of nuchal translucency measurement. Is it still effective? Obstetrics and Gynecology Science. 56 (5), 307-311. (Level 3 evidence)
Liu, Y., Ye, X., Zhang, N., Zhang, B., Guo, C., Huang, W., Jing, L., et al. (2015). Diagnostic value of ultrasonographic combining biochemical markers for Down syndrome screening in first trimester: a meta-analysis. Prenatal Diagnosis, 35 (9), 879-887. Abstract retrieved November 12, 2015 from PubMed database.
National Institute for Health and Clinical Excellence. (2017, January). Clinical guideline: antenatal care for uncomplicated pregnancies. Retrieved November 8, 2017 from http://www.nice.org.uk.
Prats, P., Rodriguez, I., Comas, C., & Puerto, B. (2014). Systematic review of screening for trisomy 21 in twin pregnancies in first trimester combining nuchal translucency and biochemical markers: a meta-analysis. Prenatal Diagnosis, 34 (11), 1077-1083. Abstract retrieved November 12, 2015 from PubMed database.
Sahota, D. S., Leung, T. Y., Chan, L. W., Law, L. W., Fung, T. Y., Chen, M., & Lau, T. K. (2010). Comparison of first-trimester contingent screening strategies for Down syndrome. Ultrasound in Obstetrics & Gynecology, 35 (3), 286-291. (Level 4 evidence)
ORIGINAL EFFECTIVE DATE: 9/11/2011
MOST RECENT REVIEW DATE: 1/10/2019
Policies included in the Medical Policy Manual are not intended to certify coverage availability. They are medical determinations about a particular technology, service, drug, etc. While a policy or technology may be medically necessary, it could be excluded in a member's benefit plan. Please check with the appropriate claims department to determine if the service in question is a covered service under a particular benefit plan. Use of the Medical Policy Manual is not intended to replace independent medical judgment for treatment of individuals. The content on this Web site is not intended to be a substitute for professional medical advice in any way. Always seek the advice of your physician or other qualified health care provider if you have questions regarding a medical condition or treatment.
This document has been classified as public information.