NSGC Practice Guideline: Prenatal Screening and Diagnostic Testing Options for Chromosome Aneuploidy

Abstract

The BUN and FASTER studies, two prospective multicenter trials in the United States, validated the accuracy and detection rates of first and second trimester screening previously reported abroad. These studies, coupled with the 2007 release of the American College of Obstetricians and Gynecologists (ACOG) Practice Bulletin that endorsed first trimester screening as an alternative to traditional second trimester multiple marker screening, led to an explosion of screening options available to pregnant women. ACOG also recommended that invasive diagnostic testing for chromosome aneuploidy be made available to all women regardless of maternal age. More recently, another option known as Non-invasive Prenatal Testing (NIPT) became available to screen for chromosome aneuploidy. While screening and testing options may be limited due to a variety of factors, healthcare providers need to be aware of the options in their area in order to provide their patients with accurate and reliable information. If not presented clearly, patients may feel overwhelmed at the number of choices available. The following guideline includes recommendations for healthcare providers regarding which screening or diagnostic test should be offered based on availability, insurance coverage, and timing of a patient's entry into prenatal care, as well as a triage assessment so that a general process can be adapted to unique situations.

Noninvasive prenatal screening for fetal aneuploidy, 2016 update: a position statement of the American College of Medical Genetics and Genomics

“…[11][12][13][14][15] This position statement replaces the 2013 "ACMG Statement on Noninvasive Prenatal Screening for Fetal Aneuploidy. " 3 We emphasize that all genetic screening has residual risk (i.e., risk of having a genetic condition even after receiving a negative or "normal" result).…”

Media portrayal of non-invasive prenatal testing: a missing ethical dimension

“…recommended for use as a second-tier screening tool for women identified as having high risk of aneuploidy [Langlois et al, 2013;Wilson et al, 2013]. There are expectations that the technology will soon become accurate enough to replace current screening methods and diagnostic tests [Norton, Rose and Benn, 2013;Oepkes et al, 2014], as well as predictions that it will be established a new standard of care for prenatal screening [Levine and Goldschlag, 2014].…”

Localizing NIPT: Practices and meanings of non-invasive prenatal testing in China, Italy, Brazil and the UK

“…The combined test determines the risk of foetal aneuploidies through an algorithm [6] that combines: a) the maternal age, b) the values of two serum markers (maternal serum pregnancy--associated plasma protein A, PAPP--A, and maternal serum Beta human chorionic gonadotrophin, beta--hCG) measured between 10+0 and 14+1 weeks of gestations, and c) the value of nuchal translucency measured with a scan at 11+2 and 14+0 weeks of gestation. The combined test offers an estimate of the individual probabilities of carrying a foetus affected by trisomy 13, 18 or 21.…”

“…The combined test offers an estimate of the individual probabilities of carrying a foetus affected by trisomy 13, 18 or 21. In addition the combined test can offer some indications to determine other congenital anomalies, such as cardiac malformations [6]. The estimate of each individual probability is compared with a pre--established cut--off (usually 1/250 in Italy, but much lower in UK and China, about 1/150): if the probability is below 1/250, the result of the combined test is considered negative; if the probability is above 1/250, the result of the test is considered positive, in which case the woman is offered the possibility to undergo an invasive cytogenetic test (CVS or amniocentesis) to confirm the result of the test.…”