Population‐based trends in the prenatal diagnosis of sex chromosome aneuploidy before and after non‐invasive prenatal testing

Abstract

Objective To assess the impact of non‐invasive prenatal testing (NIPT) on trends in the prenatal diagnosis of sex chromosome aneuploidy (SCA) in a population with >73,000 annual births. Method Retrospective population‐based cohort study from 1986–2016 of all women undergoing prenatal diagnosis before 25 weeks gestation in the Australian state of Victoria. Statistical significance was tested using the chi‐square test for trend or proportions. Results There were 2,043,345 births and 842 SCA diagnoses from 1986–2016. The percentage of prenatal diagnostic tests leading to a SCA diagnosis increased significantly from 0.95% in 2010 to 2.93% in 2016 (p < 0.001) but due to a concurrent decline in testing, the annual prenatal diagnosis rate of SCA remained stable at 4.4/10,000 births. Among confirmed fetal SCAs the most common indication for testing in 1986 was advanced maternal age (63%); in 2016 it was high risk NIPT (49%). Conclusion SCAs now make up an increasing proportion of prenatal diagnostic results but due to the overall decline in diagnostic testing, the prenatal prevalence as a percentage of births remained steady. The ascertainment of fetal SCA has evolved from an incidental finding after testing for increased risk of trisomy 21, to a diagnosis obtained after suspected SCA on NIPT.

Impact of early diagnosis and noninvasive prenatal testing (NIPT): Knowledge, attitudes, and experiences of parents of children with sex chromosome aneuploidies (SCAs)

“…To our knowledge, this is the first study to analyze parental perspectives on the impact of the early detection of SCAs using NIPT. Although previous studies have researched the impact of NIPT on diagnostic rates for SCAs, none have explored parental perspectives about how NIPT specifically affects family well‐being and the child's outcomes . Parental perception of NIPT and the diagnosis of SCAs is important to examine in order to enhance our ability to better understand the needs and concerns for families with a positive screening result in the future.…”

“…Several other major societies released similar statements, including ACMG and the National Society of Genetic Counselors (NSGC) . As a result, wider commercialization and increased access to NIPT have yielded increased identification of those at risk for SCAs . The introduction of NIPT has provided a platform in which all mothers, regardless of age or risk level, are able to access an alternate option to invasive prenatal testing to identify fetal abnormalities, as well as SCAs.…”

“…Given the increase in prenatal diagnostic rates of SCAs, as well as the introduction of large-scale utilization of NIPT, more systematic research is warranted to understand the impact of NIPT from parental perspectives. 46 This study investigated parental knowledge, attitudes, and experiences surrounding prenatal diagnosis and NIPT, as well as as well as the answer choices available to participants, are described in Therefore, this study considers any diagnosis before 12 months an early diagnosis.…”

Clinical Experience with Fetal Sex Chromosome Aneuploidy Identified by Non-Invasive Prenatal Testing in 45773 Cases

“…The incidence of SCA is estimated to be 1 in every 500 live births and about 75-90% cases are undiagnosed during their lifetime [12] . Despite having a combined prevalence greater than T21, SCA testing have not been included in prenatal screening programs, due to the frequently mild phenotype and coupled with uncertainty over the bene ts of early treatments [13] .…”

“…However, none of the screening methods was speci cally used for SCA, except where an ultrasound nding of cystic hygroma, fetal hydrops and enlarged nuchal translucency may raise suspicion of 45,X [13] . Before NIPT technology was launched, the detection of sex chromosome abnormalities was diagnosed only through culture of amniotic uid cells of high-risk pregnant women or newborn screening.…”