One-stop clinic for assessment of risk of chromosomal defects at 12 weeks of gestation

Abstract

Prenatal diagnosis of trisomy 21 requires an invasive test in women considered to be at high risk after screening. At present, there are four screening tests. For a 5% false-positive rate, the sensitivities are approximately 30% for maternal age alone, 60-70% for maternal age and second-trimester maternal serum biochemical testing, 75% for maternal age and first-trimester fetal nuchal translucency (NT) scanning, and 90% for maternal age with fetal NT and maternal serum free beta-human chorionic gonadotropin (beta-hCG) and pregnancy-associated plasma protein-A (PAPP-A) at 11-14 weeks. This article examines the methodology of first-trimester screening and summarizes the results from all studies reporting on the implementation of this method.

Evaluation of Trisomy 21 Screening by Fetal Nuchal Translucency Thickness, Maternal Age and Biochemical Serum in the South of Vietnam

“…We obtained the most of affected cases of trisomy 21 (12 /16 cases) at 2.4mm (Table 1), so we found a higher of sensitivity and a lower false positive for Down's syndrome detection in the 2.4 mm cut-off point than those in point of 2.5mm and 95th percentile (75.0% and 4.9% versus 65.8% and 3.3%; 68.8% and 4.6%, respectively). Our 75% of detection rate for trisomy 21 at this cut-off point was coincided to reported by Pandya et al [25] and Nicolaides et al [26] who used the fetal NT cut-off of point at 2.5 mm, and by Audibert et al [27] who used the fetal NT above 95th percentile.…”

“…Several studies have demonstrated a strong between an absent nasal bone at 11-14 weeks of gestation and trisomy 21 [32][33][34]. And in the combined data from these studies, the fetal nasal bone was absence in 69% of fetus with trisomy 21 [26]. In present study, the fetal structural defects of Down syndrome were poverty in anatomical ultrasound scanning at the 18-22 weeks of gestation, so an association with many approaches was useful to improve the detection rate of trisomy 21.…”

Motivations for Undertaking DNA Sequencing-Based Non-Invasive Prenatal Testing for Fetal Aneuploidy: A Qualitative Study with Early Adopter Patients in Hong Kong

“…blood test on level of alpha-fetoprotein and total human chorionic gonadotropin) in the public hospital [35]. These tests are also available in private hospitals or laboratories and typically cost between HK$ 2,000-3,000 (US$ 260-390) for SU-DSS (e.g., OSCAR; One-Stop Clinic for Assessment of Risk) [15,36] and between HK$ 4,500-7,500 (US$ 580-970) for IPD. The criteria of the risk assessment from SU-DSS are different in the public and private services.…”

“…The clinical benefits of DNA-NIPT include a reduction in the use of invasive prenatal diagnosis tests (IPD), such as chorionic villus sampling (CVS; usually performed at 10-13 weeks of gestation) and amniocentesis (performed at 15-20 weeks), which carry about a 0.5-1% procedural risk of miscarriage [12,13], and are carried out in response to relatively high false positive rates from SU-DSS [14,15]. As a consequence, DNA-NIPT could potentially reduce both direct and indirect costs of IPD among high-risk women [16].…”

As Technology Evolves, So Should Its Application

“…Ideally, the best approach to evaluating the fetus should include a first anatomic scan to be done at 11 to 14 weeks to measure the nuchal translucency (NT) for Down syndrome screening [36][37][38] followed by a second detailed follow-up scan at 20 to 22 postmenstrual weeks to look for late-developing anomalies. Because of the constraints of the gestational age at which termination of pregnancy is possible in the United States, one can also consider the transvaginal 15-to 16-week scan, which is well accepted in other countries and which can be done in addition to or in lieu of the 12-week scan (if the patient is presenting late).…”