First-Trimester Screening for Trisomies 21 and 18

Abstract

First-trimester screening for trisomies 21 and 18 on the basis of maternal age, maternal levels of free beta human chorionic gonadotropin and pregnancy-associated plasma protein A, and measurement of fetal nuchal translucency has good sensitivity at an acceptable false positive rate.

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

“…16 cases of trisomy 21 (prevalence was 1 in 156 pregnancies) were found in present study and similar to result of Wapner et al [13] (1 in 135 pregnancies), but rather higher than reported by Leung et al [14] (1 in 334 pregnancies) in China, by Dhaifalah et al [15] (1 in 343 pregnancies) in Czech and by Theodoropus et al [16] (1 in 355 pregnancies) in Greece. This difference was depended on the efficacy of prenatal screening program and the risk of obstetrical study population.…”

“…However, we didn't find out a significant correlation with trisomy 21 and the advanced of maternal age (OR = 2.45, p = 0.124) because our study was a low-risk study population (the means of maternal age was 28.9 ± 4.5 years); so it was not eligible to use the maternal age to evaluate the possibility of trisomy 21 in young obstetrical population. Furthermore, according to Nicolaides et al [1,19] maternal age screening had also a low detection rate (30%) for prediction of trisomy 21 and it also showed no advantage for using maternal age alone in comparison into the combined of fetal NT thickness and biochemical serum [13]. Similarly, Niemimaa et al [20] believed that trisomy screening by using of maternal age alone has a low detection rate and a high false positive rate.…”

“…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. Because the absence of the nasal bone is not related to fetal NT thickness [31], and the finding screening of maternal age alone showed no advantage for detection of trisomy 21 [13], therefore, they could be combined relatively simply to provide a more effective method of early screening for trisomy 21 [6,33].…”

Use of the combined first‐trimester screen result and low PAPP‐A to predict risk of adverse fetal outcomes

“…First-trimester screening (FTS) has been identified as an effective screen for trisomy 21 (Wapner et al, 2003;Avgidou et al, 2005) with detection rates of approximately 90% and low false positive rates were achieved Wapner et al, 2003). This technique uses fetal nuchal translucency (NT) and maternal serum markers of free beta-human chorionic gonadotropin (free β-hCG) and pregnancy associated plasma protein-A (PAPP-A) at 10 to 14 weeks of gestation which are combined to give a risk assessment and stratify women as high or low risk (Snijders et al, 1998;Spencer et al, 1999).…”

Utilization of available prenatal screening and diagnosis: effects of the California screen program

“…In large cohorts, combined first-trimester nuchal translucency (NT) and serum analyte measurements can detect approximately 80-85% of fetuses affected by Down syndrome, a detection rate that is similar to that of second-trimester analyte screening. 1,2 Despite recommendation by the American College of Obstetricians and Gynecologists and other medical societies to universally offer first trimester screening, 3 some states have yet to incorporate first-trimester screens into government-funded aneuploidy screening programs.…”