How Effective Is First-Trimester Screening for Trisomy 21 Based on Ultrasound Only?

OBJECTIVE: To evaluate the most common first-trimester ultrasound features of fetuses with trisomy 21 (T21) and to examine the screening performance for Down syndrome (DS) using only ultrasound-based protocols. To investigate whether maternal age (MA) has an impact on the efficacy of the ultrasound-based screening methods. METHODS: In a prospective study, 6,265 patients were examined. Two ultrasound-based risk calculation protocols were applied: 'NT' (based on nuchal translucency) and 'NT+' (based on NT and secondary markers). RESULTS: A total of 5,696 patients were enrolled for analysis; 84 subjects with T21 were identified. Combinations of abnormal ultrasound markers were observed in only 1.2% of euploid fetuses compared to 71.5% of fetuses with T21. Among 17.9% of DS cases with cardiac anomaly, 14.3% comprised atrioventricular septal defects. For a false-positive rate of 3%, the detection rates of T21 were 73.8 and 91.7% for the 'NT' and 'NT+' protocols, respectively. The efficacy of both methods was affected by MA. CONCLUSIONS: Most of the fetuses with DS demonstrate a combination of ultrasound markers of aneuploidy in the first trimester. The 'NT+' protocol is efficient and provides comparable performance as a combined screening test. It is a valuable method, especially when the access to biochemical analysis is restricted.

How effective is ultrasound-based screening for trisomy 18 without the addition of biochemistry at the time of late first trimester?

UNLABELLED: Trisomy 18 (T18) remains the second most common aneuploidy. It is associated with multiple congenital anomalies and causes intrauterine fetal demise in the most severe cases. OBJECTIVES: To examine the screening performance of ultrasound-based protocols for detecting T18, we aimed to determine the most common signs and their prevalence in fetuses with T18 to develop logistic regression model. METHODS: This was a prospective study based on singleton pregnancies examined at gestation 11+0 to 13+6. The referrals constituted 6210 patients. Scan protocol enclosed a systematic review of the entire early fetal anatomy, including fetal cardiac evaluation and sonographic signs of aneuploidy. RESULTS: Our study population comprised 5650 pregnancies: 5613 cases with a normal karyotype and 37 cases with T18. The mean nuchal translucency (NT) thickness in the subgroup of euploidy was 1.7 and in the subgroup of T18 it was 5.4. No statistically significant differences were found in terms of maternal age. One case of T18 (2.7%) demonstrated no markers of aneuploidy as opposed to 5111 cases of euploidy (91.1%). Extracardiac malformations were identified in 13 cases of T18 (35.1%) and in 48 cases of euploidy (0.8%). Congenital heart defects were observed in 26 cases of T18 (70.3%) and in 27 cases of euploidy (0.5%). CONCLUSIONS: Our results showed good screening performance of ultrasound-based risk calculation models. When the first trimester pattern of T18 is considered, an increased NT, tricuspid regurgitation, single umbilical artery, omphalocele and right dominant heart should be specifically searched for.

First trimester severe ductus venosus flow abnormalities in isolation or combination with other markers of aneuploidy and fetal anomalies.

BACKGROUND: Altered flow in ductus venosus (DV) may be caused by the changes in preload or afterload. Its association with aneuploidy and congenital heart defects (CHDs) was widely described. OBJECTIVES: The aim of this study was to examine the incidence of a reversed a-wave in DV flow (revDV) and the absence of DV (noDV), their coincidences with other markers of aneuploidy or fetal abnormalities in a mixed-risk population. METHODS: The study group covered women who underwent an ultrasound scan between 11+0 and 13+6 weeks' gestation. Applied inclusion criteria: Singleton pregnancies with known pregnancy outcome and a crown-rump length of 45-84 mm. RESULTS: A total of 5811 cases, including 137 aneuploidies, met the inclusion criteria: 35 subjects of noDV, 189 of revDV and 5587 of normal DV flow. The incidence of noDV in euploidy was 0.47%, and in aneuploidy 5.8%. The incidence of revDV in euploidy was 2.46%, and in aneuploidy 35.7%. Among aneuploidy, the highest prevalence of noDV was found in monosomy 45X. revDV showed the highest prevalence in trisomy 18. Isolated noDV was only found in euploidy. Isolated revDV subjects were only observed in euploidy and trisomy 21. Any combination of revDV with additional markers showed high incidence in major trisomies. Extracardiac anatomy and abnormal cardiac findings showed a higher prevalence in noDV and revDV cases. CONCLUSIONS: The presence of noDV might be useful in suspicion of monosomy X among cases with increased nuchal translucency, as well as in differentiating them from other aneuploidies. The combinations of aneuploidy markers with revDV are strong indicators of aneuploidy. revDV alone is a poor screening tool for aneuploidy and euploidy with CHD.