Selection of prenatal screening with nuchal translucency > 95th centile and below 99th centile: a 4-year observational study with real-world data

OBJECTIVE

We sought to analyze the genetic outcomes of fetuses with nuchal translucency (NT) > 95th centile, and determine whether prenatal genetic counseling, chromosomal microarray analysis (CMA) or non-invasive prenatal testing (NIPT) are truly beneficial for the outcomes of fetuses with increased NT > 95th centile and below 99th centile.

MATERIALS AND METHODS

A total of 535 pregnant women were included in this study, with a fetal NT > 95th centile at 11-13+6 weeks of gestation from January 2017 to December 2020. 324 pregnant women with fetal NT > 95th centile and below 99th centile combined with other risk factors and NT > 99th centile received prenatal diagnostic karyotype analysis and CMA, and 211 pregnant women with fetal isolated increased NT > 95th centile and below 99th centile were selected to carry out NIPT.

RESULTS

A total of 211 pregnant women who underwent NIPT were included in the study, NIPT results showed that 8 high-risk cases were confirmed by prenatal diagnosis. Overall, the detection rate of NIPT was 3.79%. A total of 324 pregnant women with fetal NT > 95th centile and below 99th centile, along with other risk factors, and those with fetal NT > 99th centile, received karyotype analysis and CMA for prenatal diagnosis. Among them, a total of 73 genetic abnormalities were detected, including 45 cases of chromosomal aneuploidy, 7 cases of structural abnormalities, and 21 cases of copy number variations (CNVs) with a size of less than 10 Mb. In addition, the 73 women with genetic abnormalities are divided into three groups based on the NT measurement (Group 1: Fetuses with NT > 95th centile and below 99th centile, Group 2: Fetuses with NT > 99th centile, and Group 3: Fetuses with NT > 99th centile). 13.11% (8/61) of pathogenic genetic abnormalities (6 chromosomal aneuploidy, 1 structural abnormality, and 1 likely pathogenic CNV) will be missed if genetic counseling and prenatal genetic testing were not conducted in fetuses with increased NT > 95th centile and below 99th centile combined with other risks. Pathogenic CNVs were the most common abnormalities in group 3, and one likely pathogenic CNV was detected in group 1 and group 3, respectively, and a total of 14 CNVs of unknown clinical significance (VOUS) were detected.

CONCLUSIONS

Through this study, we demonstrated that the critical value of NT > 95th centile for invasive detection or NIPT. Invasive testing combined with CMA may be recommended for fetuses with NT > 95th centile and below 99th centile and with other risks. But when isolated NT > 95th centile and below 99th centile, NIPT would be appropriate.

Whole exome sequencing in fetuses with isolated increased nuchal translucency: a systematic review and meta-analysis

OBJECTIVE

To estimate the incremental yield of detecting pathogenic or likely pathogenic diagnostic genetic variants (DGV) by whole exome sequencing (WES) over standard karyotype and chromosomal microarray (CMA) analyses in fetuses with isolated increased nuchal translucency (NT) and normal fetal anatomy at the time of 11-14 weeks scan.

MATERIALS AND METHODS

Medline and Embase databases were searched. Inclusion criteria were fetuses with NT >95^th percentile, normal karyotype and CMA and no associated structural anomalies at the time of the 11-14 weeks scan. The primary outcome was to estimate the incremental yield of detecting pathogenic or likely pathogenic genetic variants by WES over standard karyotype and CMA analyses in fetuses with isolated increased nuchal translucency. The secondary outcomes were the detection of a genetic variant of unknown significance. Sub-analysis according to different NT cutoffs (between 3.0 and 5.5 mm and > 5.5 mm) and considering fetuses with isolated NT in which fetal anatomy was confirmed to be normal at the anomaly scan were also performed. Random effects model meta-analyses of proportion were used to analyze the data.

RESULTS

Eight articles (324 fetuses) were included in the systematic review. Of the fetuses with negative standard karyotype and CMA analysis, the 8.07% (95% CI 5.4-11.3) had pathogenic or likely pathogenic genetic variants detected exclusively by WES. When stratifying the analysis according to NT cutoffs, genetic anomalies detected exclusively at WES analysis were found in 44.70% (95% CI 26.8-63.4) of fetuses with NT between 3.0 mm and 5.5 mm and 55.3% (95% CI 36.6-73.2) in those fetuses with NT >5.5 mm and positive WES results. The 7.84% (95% CI 1.6-18.2) had variants of unknown significance identified by WES. When considering fetuses with isolated increased NT and normal fetal anatomy at the anomaly scan, the rate of pathogenic or likely pathogenic genetic variants detected by WES was 3.87% (95% CI 1.6-7.1), while variants of unknown significance were detected in 4.27% (95% CI 2.2-7.0) of cases.

CONCLUSIONS

Pathogenic and likely pathogenic genetic variants detected by WES are present in a significant proportion of fetuses with increased NT but normal standard karyotype and CMA analysis, also when no anomalies are detected at the anomaly scan. Further large studies sharing objective protocols of imaging assessment are needed to confirm these findings and to elucidate which gene panels should be assessed in fetuses with isolated increased NT to rule out associated genetic anomalies, which may potentially impact post-natal outcomes.

Prenatal diagnosis and perinatal outcomes of twin pregnancies disharmonious for one fetus with nuchal translucency above the 95th percentile

OBJECTIVE

To assess prenatal diagnosis and pregnancy outcomes in twin pregnancies where one fetus has nuchal translucency (NT) above the 95th percentile.

METHOD

In this retrospective analysis, 130 twin pregnancies (260 fetuses) in which one twin had an NT measurement above the 95th percentile while that of the other twin was normal were analyzed. Prenatal diagnostic results such as G bands, chromosomal microarray analysis, ultrasound findings, and pregnancy outcomes were reviewed.

RESULTS

Karyotype analysis and CMA results revealed that 15 (15.6 percent, 15/96) fetuses exhibited chromosomal abnormalities and that 13 fetuses were Variant of Uncertain Significance. Chromosome abnormalities were detected at a rate of 8.9% (5/56) in the DCT group and 25.0% (10/40) in the MCT group (p = 0.033, X2 = 4.571). 2 fetuses in DCT (3.9 percent, 2/51) and 4 fetuses in MCT (13.3 percent, 4/30) (p = 0.187) revealed structural abnormalities among the cases with normal prenatal diagnosis. Fetuses in the DCT group had an overall survival rate of 75.4 percent (95/126), whereas those in the MCT group had a survival rate of 60.4 percent (81/134) (p = 0.01, X2 = 6.636). According to the findings of Logistics regression analysis, NT thickening, maternal age and method of conception were all significant risk factors for chromosome abnormalities.

CONCLUSION

In twin pregnancies with one fetus with NT above the 95th percentile, the prevalence of fetal structural abnormalities of the MCT group and the DCT group were comparable. Pregnant women's age and mode of pregnancy are risk factors for chromosomal abnormalities.

Identification of Fetuses at Increased Risk of Trisomies in the First Trimester Using Axial Planes

INTRODUCTION

The measurement of nuchal translucency (NT) is crucial for assessing risk of aneuploidies in the first trimester. We investigate the ability of NT assessed by a transverse view of the fetal head to detect fetuses at increased risk of common aneuploidies at 11-13 weeks of gestation.

METHODS

We enrolled a nonconsecutive series of women who attended our outpatient clinic from January 2020 to April 2021 for aneuploidy screening by means of a first trimester combined test. All women were examined by operators certified by the Fetal Medicine Foundation. In each patient, NT measurements were obtained both from the median sagittal view and transverse view. We calculated the risk of aneuploidy using NT measurements obtained both with sagittal and axial scans, and then we compared the results.

RESULTS

A total of 1,023 women were enrolled. An excellent correlation was found between sagittal and transverse NT measurements. The sensitivity and specificity of the axial scan to identify fetuses that were deemed at risk of trisomy 21 using standard sagittal scans were 40/40 = 100.0% (95% confidence interval [CI]: 91.2-100.0) and 977/983 = 99.4% (95% CI: 98.7-99.7), respectively. The sensitivity and specificity of the axial scan to identify fetuses at risk of trisomy 13 or 18 were 16/16 = 100.0% (95% CI: 80.6-100.0) and 1,005/1,007 = 99.8% (95% CI: 99.3-99.9).

CONCLUSIONS

When the sonogram, a part of combined test screening, is performed by an expert sonologist, axial views can reliably identify fetuses at increased risk of trisomies without an increase in false negative results.

Pregnancy outcomes of normal karyotype fetuses with increased nuchal translucency

Background

Although the association between first-trimester increased nuchal translucency (NT) and chromosomal defects is well-defined, there is little knowledge about the importance of increased NT in fetuses with normal karyotypes. Hence, this study was designed to evaluate outcomes of normal karyotype fetuses with increased NT.

Methods

This observational retrospective study was conducted on 720 pregnancies with increased NT (>3mm) at 11 to 13 weeks of gestational age in Yas Hospital, Tehran, Iran, from 2016 to 2020. Study outcomes were incidence of preeclampsia, intrauterine growth restriction) IUGR (, preterm labor, fetal anomaly, cardiac malformations, hydrops fetalis, abortion, and intrauterine fetal death (IUFD) in pregnancies without evident chromosomal karyotype abnormalities.

Results

Out of 720 participants who underwent karyotyping in the study center, 523 fetuses had normal karyotype results. In the pregnancies assessed for outcome, 357 (68.3%) reached live birth, 104 (19.9%) aborted, and 62 (11.9%) resulted in IUFD. Study outcomes including preeclampsia (<0.001), IUGR (<0.001), preterm labor (<0.001), fetal anomaly (<0.001), cardiac malformations (<0.001), hydrops fetalis (0.017), abortion (<0.001), and IUFD (<0.001) resulted in a statistically significant difference in the distribution of cases across NT intervals.

Conclusion

This study demonstrated adverse pregnancy outcomes increased with increasing NT despite normal karyotyping. Hence, tight observation of mothers and fetuses should be done in normal karyotype fetuses with increased NT.

16p13.11 microdeletion/microduplication in fetuses: investigation of associated ultrasound phenotypes, genetic anomalies, and pregnancy outcome follow-up

OBJECTIVES

16p13.11 microdeletion/microduplication are rare genetic diseases with incomplete penetrance, most of which have been reported in adults and children, with ultrasound phenotyping in fetuses rarely described. Here, we have analyzed prenatal ultrasound phenotypic characteristics associated with 16p13.11 microdeletion/microduplication, in order to improve the understanding, diagnosis and monitoring of this disease in the fetus.

METHODS

A total of 9000 pregnant women who underwent invasive prenatal diagnosis for karyotyping and SNP-array were retrospectively analyzed in tertiary referral institutions from October 2016 to January 2022.

RESULTS

SNP-array revealed that 20 fetuses had copy number variation (CNV) in the 16p13.11 region, out of which 5 had 16p13.11 microdeletion and the rest showed microduplication, along with different ultrasound phenotypes. Furthermore, 4/20 cases demonstrated structural abnormalities, while the remaining 16 cases were atypical in ultrasound. Taken together, 16p13.1 microdeletion was closely related to thickened nuchal translucency, while 16p13.11 microduplication was more closely associated with echogenic bowel. Only 5/15 fetuses were verified by pedigree, with one case of 16p13.11 microdeletion being de novo, and the other cases of 16p13.11 microduplication were inherited from one parent. In 4/20 cases, the pregnancy was terminated. Except for one case with short stature and another one who underwent lung cystadenoma surgery, no abnormalities were reported in the other cases during follow-up.

CONCLUSION

Fetuses with 16p13.11 microdeletion/microduplication had no characteristic phenotype of intrauterine ultrasound and was in good health after birth, thus providing a reference for the perinatal management of such cases.

Does isolated nuchal translucency from 2.5 to 2.9 mm increase the risk of fetal chromosome disease?

Increased fetal nuchal translucency (NT) is a common ultrasonic manifestation during pregnancy. Many studies have confirmed that NT ≥ 3 mm is a high risk factor for adverse pregnancy outcome. However, when NT is between 2.5 and 2.9 mm, will it increase the risk of fetal chromosome abnormalities and other diseases? What is the most appropriate method for prenatal chromosome evaluation? At present, it has not been widely reported in the literature, and the conclusion is also controversial. This prospective cohort study included fetal samples from women who underwent amniocentesis from 2017 to 2020. The samples of the experimental group were fetuses with NT ≥ 2.5 mm at 11 to 13 + 6 weeks of gestation, with or without ultrasonographic anomaly. The control group contained fetal NT < 2.5 mm without ultrasonographic anomalies. All amniotic fluid samples were tested by copy number variants sequencing. In 262 fetal samples with isolated NT from 2.5 to 2.9 mm, the detection rate of aneuploidy was 3.4% (9/262), and the risk of aneuploidy was significantly higher than that of the control group (1.4%, 32/2331) (relative risk 2.5, 95% CI 1.2-5.2). The detection rates of other pathogenic/likely pathogenic copy number variants in the two groups were 0.8% (2/262) and 1.3% (31/2331), respectively, which was not statistically significant (relative risk 0.6, 95% CI 0.1-2.4). Our results showed that isolated NT from 2.5 to 2.9 mm increased the risk of fetal chromosome aneuploidy. Therefore, noninvasive prenatal screening is recommended as the first choice for prenatal chromosome evaluation in this population.

Relationship between extreme values of first trimester maternal pregnancy associated plasma Protein-A, free-β-human chorionic gonadotropin, nuchal translucency and adverse pregnancy outcomes

OBJECTIVE

The aim of our study was to investigate the relationship between extreme values of first trimester screening markers and adverse obstetric outcomes.

MATERIALS AND METHODS

Our study was conducted by examining the prenatal and postnatal perinatal records of 786 singleton gestations between the ages of 18-40, who applied to Prof. Dr. Cemil Taşçıoğlu City Hospital outpatient clinics for first-trimester screening for aneuploidy, between January 1, 2017 and December 31, 2019.

RESULTS

The presence of small for gestational age (SGA) was found to be statistically significant for the <5 percentile (<0.37) pregnancy-associated plasma protein A (PAPP-A) group (p = 0.016). For <5 percentile β-hCG group, the presence of gestational diabetes mellitus (GDM), premature rupture of membrane (PROM) and preterm premature rupture of membrane (PPROM) was determined as a statistically significant risk (p = 0.015, p = 0.005, p = 0.02 respectively) In the univariate test, fetal death rate was found to be high for ≥90 percentile at nuchal translucency (NT), but the presence of fetal death was found to be statistically insignificant in logistic regression analysis. (p: 0.057).

CONCLUSION

First trimester screening test can be used in predicting pregnancy complications. In this study we found that serum levels of PAPP-A are associated with developing SGA, while GDM, PROM and PPROM are more common in low serum free β-hCG.

Angiogenic factors measured in aspirated placental tissue between the 10 + 6 and 18 + 3 weeks of gestation

This study was designed to determine the level of vascular endothelial growth factor-A (VEGF-A), basic fibroblast growth factor (bFGF) and endothelial nitric oxide synthase (eNOS) in chorionic villi during in first and second trimester, and their association with nuchal translucency (NT) measured by ultrasound. Seventy-five singleton healthy pregnancies with no detected congenital malformation were collected for NT measurements and chorionic villus sampling (CVS). Concentrations of angiogenic factors were assayed in chorionic villi sampled between 10 + 6 and 18 + 3 weeks of gestation. ENOS level was steady during this gestational period, while the concentrations of VEGF-A and bFGF significantly decreased. Placental concentrations of VEGF-A and bFGF correlated positively with each other (semi-partial correlation in multivariable linear regression (r): 0.90) and both correlated negatively with the eNOS level (r: -0.64 and r: -0.83, respectively). NT was positively correlated with eNOS concentration and negatively correlated with bFGF levels (r: 0.85 and r: -0.78, respectively). Inverse correlation was found between gestational age and VEGF-A and bFGF concentrations (r: -0.57 and r: 0.73, respectively). Alterations of angiogenic factors in chorionic villi might be an adjunct modality to NT and foetal growth as sonographic markers.

Is nuchal translucency measurement feasible in early pregnancy?

BACKGROUND

To investigate whether early nuchal translucency measurement at 7+0 to 9+0 weeks (NT7-9w) is feasible, obtain normal values for different crown-rump lengths (CRL) in the above weeks and create percentile tables.

METHODS

A prospective study was conducted in the Obstetrics and Gynecology Department of the University Hospital of Ioannina, including data from women with singleton pregnancies, examined in the early pregnancy unit between November 2010 and May 2015 at a CRL of 10-27 mm. The early pregnancy scan was performed vaginally, and the NT7-9w, CRL, fetal heart rate, and mean yolk sac diameter were measured. Demographic data, including body mass index and smoking, were recorded.

RESULTS

NT7-9w was measured successfully in 192 fetuses out of 210 (91.4 %), with a CRL ranging from 10-27 mm. The median maternal age was 31 (range 18-43) years, and the median CRL was 19.9 (range 10.0-27.0) mm. Considering the above measurements, we created normal values and percentiles tables of NT at 7+0 to 9+0 weeks in relation to the corresponding CRL measurement.

CONCLUSION

According to the literature, this is the first attempt to measure NT in such weeks of pregnancy. NT measurement as early as 7+0 to 9+0 is feasible and normal values can be created and correlated with CRL measurements. HIPPOKRATIA 2021, 25 (4):151-155.

Long-term outcome of fetus with ameliorated cystic hygroma

OBJECTIVE

Cystic hygroma often ameliorates or disappears with pregnancy progression. Fetuses/neonates with amelioration, when without chromosomal or major structural abnormality, generally show a favorable outcome at birth. The present study was aimed to clarify the short/long-term outcomes of fetuses/neonates with the amelioration of cystic hygroma during pregnancy.

MATERIAL AND METHODS

This was a retrospective observational study. We focused on fetuses with cystic hygroma managed in our institute between January 2006 and June 2019. The infants were followed by pediatricians (neonatologist, pediatric cardiologist, and pediatric neurologist) and pediatric outcomes were retrieved from the medical records up to 3 years old.

RESULTS

One hundred and seven fetuses with cystic hygroma were included. Of the 107, cystic hygromas ameliorated in 31 fetuses (31/107: 29%). Of the 31, there were 26 livebirths. Half (n = 13) of the 26 fetuses had a good outcome, whereas the remaining half (n = 13) had abnormalities. Various abnormalities were detected in their infancies. A nuchal thickness (diameter of hygroma) of ≥5 mm was significantly correlated with abnormalities (P = 0.047).

CONCLUSION

Physicians should pay attention to fetuses/neonates with ameliorated cystic hygroma. Of those, special attention should be paid to fetuses/neonates with a nuchal thickness at diagnosis ≥5 mm.

Real-time quality control of nuchal translucency measurements using the exponentially weighted moving average chart

OBJECTIVE

The establishment of ongoing audits for first-trimester nuchal translucency (NT) measurements is of paramount importance. The exponentially weighted moving average (EWMA) chart has been published as an efficient tool for NT quality control with the advantages of being suitable for real-time long-term monitoring. This study aimed to assess the efficacy of real-time NT quality control using EWMA charts.

MATERIALS AND METHODS

This was an ongoing prospective study conducted from January 2011 to December 2017 at the Centre for Fetal Medicine Gennet in Prague. The quality of NT measurements was assessed using the NT retrospective distribution parameters and EWMA charts, and the results were presented to the sonographers during collective meetings.

RESULTS

Overall, 28,928 NT measurements obtained from six sonographers were eligible for the study. Looking at individual EWMA charts, we observed four main outcomes. First, there was a clear improvement in the performance of sonographers with initially poor performances. Second, the performance of sonographers with an initially satisfactory quality was maintained. Third, there was an observed deterioration of the performance without the audits. Last, the sonographers appreciated an unequivocal and straightforward graphical presentation of EWMA curves.

CONCLUSION

EWMA proved to be an efficient and suitable tool for real-time monitoring of NT quality and led to an overall improvement of the sonographers' performance.

First trimester genetic sonogram for screening fetal Down syndrome: A population-based study

OBJECTIVE

To evaluate the performance of first trimester sonomarkers in the detection of fetal Down syndrome among Thai pregnant women.

MATERIALS AND METHODS

Pregnant women at 11-13⁺⁶ weeks' gestation underwent ultrasound examination for assessment of nuchal translucency (NT), nasal bone (NB), tricuspid regurgitation (TR), and abnormal ductus venosus (aDV) Doppler waveforms. The women were followed up for final outcomes. Fetal abnormalities other than trisomy 21 were excluded. The performances of each sonomarker and their combinations in predicting fetal Down syndrome were calculated.

RESULTS

A total of 7820 pregnant women meeting the inclusion criteria were available for analysis, including 20 cases with fetal Down syndrome and 7800 unaffected cases. Of the four sonomarkers, NT, as a single sonomarker, had the highest detection rate (55.0% at a false positive rate of about 5%), whereas the remaining single sonomarkers had low detection rate (15-20%). The combination of all sonomarkers had the highest detection rate of 70% but the false positive rate was as high as 10.8%. The combination of NT and NB had a detection rate of 60% with an acceptable false positive rate of 6.9%, whereas the other combinations yielded relatively high false positive rates.

CONCLUSION

The first trimester genetic sonogram in screening for Down syndrome among Asian women is acceptably effective and may be offered to some selected groups of the population. NT is the best sonomarker with a detection rate of 55% at 5% false positive rate and its combination with NB can improve performance with minimal increase in false positive rate.

Prenatal diagnosis of partial monosomy 8p (8p23.2→pter) and partial trisomy 15q (15q21.2→qter) and incidental detection of a familial chromosome translocation of paternal origin in a pregnancy associated with increased nuchal translucency and an abnormal maternal serum screening result

OBJECTIVE

We present partial monosomy 8p (8p23.2→pter) and partial trisomy 15q (15q21.2→qter) and incidental detection of a familial chromosome translocation of paternal origin in a pregnancy associated with increased nuchal translucency (NT) and an abnormal maternal serum screening result.

CASE REPORT

A 29-year-old primigravid woman underwent chorionic villus sampling (CVS) at 13 weeks of gestation because of an increased NT thickness of 3.2 mm at 12 weeks of gestation and an abnormal maternal serum screening for Down syndrome result with a calculated risk of 1/29. Her husband was 33 years old, and there was no family history of congenital malformations. CVS revealed a derived chromosome 8 or der(8). Cytogenetic analysis of the parents revealed a karyotype of 46,XY,t(8;15)(p21.3;q13) in the father and a karyotype of 46,XX in the mother. The CVS result was 46,XY,der(8)t(8;15)(p21.3;q13)pat. The woman requested for amniocentesis at 16 weeks of gestation. Array comparative genomic hybridization (aCGH) analysis on the DNA extracted from uncultured amniocytes revealed a result of arr 8p23.3p23.2 (191,530-2,625,470) × 1.0, arr 15q21.2q26.3 (50,903,432-102,338,129) × 3.0 with a 2.434-Mb deletion of 8p23.3-p23.2 including DLGAP2, CLN8 and ARHGEF10, and a 51.435-Mb duplication of 15q21.2-q26.3 including CYP19A1 and IGF1R. Conventional cytogenetic analysis of cultured amniocytes revealed the result of 46,XY,der(8) t(8;15)(p23.2;q21.2)pat in the fetus. The pregnancy was subsequently terminated, and a malformed fetus was delivered with characteristic craniofacial dysmorphism.

CONCLUSION

Maternal serum screening and NT screening may incidentally detect familial unbalanced reciprocal translocations, and aCGH analysis is useful for a precise determination of the breakpoints of the translocation and the involvement of the related genes under such a circumstance.

Impact of Increased Nuchal Translucency Values on Pregnancy Outcomes: A Tertiary Center Experience

We evaluated the association of nuchal translucency (NT) values above 99th percentile with perinatal outcomes. Materials and methods: Singleton pregnancies with NT values above 99th percentile were investigated. Pregnancies were divided into 3 groups: group 1, NT = 2.6-<3.5 mm; group 2, NT = 3.5-4.5 mm; and group 3, NT > 4.5 mm. Demographic features, clinical characteristics, structural/chromosomal anomaly rates and perinatal outcomes were compared. Results: Normal ultrasonographic anatomy was found in 47.5%, 7.7%, and 14.3% of groups 1, 2, and 3, respectively (p = 0.006). Group 3 had the lowest normal karyotype rate (44.6%) (p = 0.005). Higher frequencies for both miscarriage and pregnancy termination were observed in group 3 compared to group 1 (8.9% vs. 4.9% and 66.1% vs. 32.7%, respectively) (p = 0.02). The lowest rate of normal postnatal anatomic findings was found in group 3 (10.7%) (p = 0.01). Conclusion: NT values above 99th percentile for gestational age seem to be associated with increased rates of chromosomal/structural abnormalities and adverse perinatal outcomes.

Prenatal diagnosis of a fetus with mosaic ring chromosome 13: Case report and review of the literature

OBJECTIVE

To diagnose the ring chromosome 13 (r(13)) in a fetus, and analyze the genotype-phenotype correlation.

CASE REPORT

A 26-year-old woman who was second pregnancy, underwent amniocentesis at 18 weeks of gestation because of the increased nuchal translucency (NT). Prenatal ultrasound showed the NT thickness was 3.5 mm at 12⁺¹ weeks of gestation and nuchal fold (NF) was 6.1 mm at 18 weeks of gestation, and amniotic fluid karyotype analysis revealed mosaic r(13). CMA detected a 16.293 Mb duplication at 13q21.32q31.1 and 31.303 Mb deletion at 13q31.1q34.

CONCLUSION

R(13) is a very rare chromosomal abnormality. Cytogenetic examination combined with CMA can provide accurate diagnosis and effective information for genetic counseling.

Rare chromosomal abnormalities: Can they be identified using conventional first trimester combined screening methods?

Objective

To evaluate the performance of first trimester combined screening for the detection of rare chromosomal abnormalities, other than Trisomies 21, 18 or 13 or 45 × .

Study design

A database containing 36,254 pregnancies was analyzed. These patients were recruited at 15 US centers and included singleton pregnancies from 10 3/7–13 6/7 weeks. All patients had a nuchal translucency (NT) scan and those without a cystic hygroma (N = 36,120) underwent a combined first trimester screening test ('FTS' - NT, PAPP-A and fbHCG). A risk cut-off of 1:300, which was used for defining high risk for Trisomy 21, was also used to evaluate the detection rate for rare chromosomal abnormalities using the combined FTS test.

Results

36,120 patients underwent combined FTS. Of these, 123 were found to have one of the following chromosomal abnormalities: Trisomy 21, Trisomy 18, Trisomy 13 or Turner syndrome. This study focuses on 40 additional patients who were found to have ‘other’ rare chromosomal abnormalities such as triploidy, structural chromosomal abnormalities, sex chromosome abnormalities or unusual chromosomal abnormalities (e.g. 47XX + 16), giving an incidence of 1.1 in 1000 for these rare chromosomal abnormalities. Of these 40 pregnancies, only 2 (5%) had an NT measurement of ≥3 mm. The detection rate for combined FTS, using a risk cut-off of ≥1:300, was 35 % (14 of 40 cases). Therefore, 65 % of cases of rarer fetal chromosomal abnormalities had a ‘normal’ combined FTS risk (<1:300) and 95 % had a ‘normal’ NT (<3 mm).

Conclusion

Traditional FTS methods are unable to identify the vast majority of rare chromosomal abnormalities. Our data do not support the potential detection of rare fetal chromosomal abnormalities as a reason to favour nuchal translucency-based first trimester screening over NIPT.

Distribution of nuchal translucency thickness at 11 to 14 weeks of gestation in a normal Turkish population

Background/aim

The aim of this study was to determine fetal nuchal translucency (NT) thickness nomogram values in first trimester in a Turkish population and compare them with previously reported European and Asian nomogram data.

Material and methods

Ultrasonographic measurements of crown-rump length (CRL) and NT thicknesses were obtained from 11 to 14 weeks of gestation in a normal Turkish population. Pregnant women with singleton pregnancy and fetal CRL between 45 and 84 mm were included in the study. The mean 1st, 3rd, 5th, 50th, 90th, 95th, 97th, and 99th percentiles and fixed cut off values of ≥ 2.5 mm, ≥ 3 mm, ≥ 3.5 mm NT thicknesses for a CRL between 45 and 84 mm were determined.

Results

A total of 1605 healthy fetuses were enrolled in the study. The sonographic measurements were performed on 1541 (%94) fetuses transabdominally and on 99 cases (%4) by the transvaginal route. The mean NT thickness for CRL between 45 and 84 mm was 1.57 ± 074 mm, and the mean 95th, 97th, and 99th percentiles of these values were 2.82 mm, 3.17, and 4.75 mm, respectively. The incidence of NT thicknesses at fixed points of ≥ 2.5 mm, ≥ 3 mm, and ≥ 3.5 mm in normal fetuses were 6.7%, 4.1%, and 2.1%, respectively.

Conclusion

The present study demonstrated the nomogram data of fetal NT thickness in a Turkish population. We think that this report will be useful for further research related to NT thickness values on the prenatal diagnosis for the first trimester chromosomal abnormalities in Turkish populations.

Structural abnormalities of chromosome 8 and fetoplacental discrepancy: A second case report and review of fetal phenotype of 8p inverted duplication deletion syndrome

We described a new second case of fetoplacental discrepancy involving first trimester prenatal detection of mosaic isochromosome i (8) (q10). A 32-year-old woman underwent chorionic villous sampling because of increased fetal nuchal translucency. Analysis of direct chromosome preparations was performed by R-banding and FISH using subtelomeric, centromeric and whole chromosome painting probes for chromosome 8 showing the presence of an isochromosome 8q with a complex, female mosaic karyotype: mos 46,XX,i (8) (q10)[13]/46,XX,del (8) (p23)[10]. Cytogenetic analysis of cultured CVS showed an interstitial duplication with concomitant terminal deletion of the short arm of chromosome 8: 46,XX,der (8)del (8) (p23)dup (8) (p?)[18]. Array-CGH analysis from cultured trophoblasts and fetal tissues revealed a 6.69 Mb terminal deletion in 8p23.3p23.1 associated with a 31.49 Mb duplication in 8p23.1p11.1. FISH analysis confirmed the 8p inverted duplication deletion syndrome. Moreover, polymorphic DNA marker analysis demonstrated that the derivative chromosome 8 was of maternal origin. FISH analysis of cultured peripheral blood lymphocytes showed that the mother also carried a cryptic paracentric inversion inv (8) (p23). Our report contributes to expand the fetal phenotype of 8p inverted duplication deletion syndrome and also provides further insight into the underlying mechanism of this rare genomic disorder.

[Genetic analysis and clinical phenotype of a family with lymphedema-distichiasis syndrome]

OBJECTIVE

To identify the genetic causes of a family with lymphedema-distichiasis syndrome (LDS).

METHODS

The whole exome sequencing was performed in a aborted fetus as the proband, and a candidate gene was identified. Peripheral blood of 8 family members were collected. Genotypic-phenotypic analysis were carried out through PCR amplification and Sanger sequencing.

RESULTS

The proband, and the mother, grandmother, uncle, granduncle of the proband all had distichiasis or varix of lower limb carried a FOXC2:c.595dupC frame shift mutation, and other subjects without any significant phenotypes did not present the mutation.

CONCLUSIONS

The FOXC2:c.595dupC frame shift mutation is the genetic cause of this family, which can lead to autosomal dominantly LDS, presenting nuchal translucency thickening and hydrops fetal during pregnancy, and the prognosis is usually good.

ACR Appropriateness Criteria® Nuchal Translucency Evaluation at 11 to 14 Weeks of Gestation

A fetus with an increased nuchal translucency at 11 to 14 weeks gestation is at risk for aneuploidy, genetic syndromes, structural anomalies, and intrauterine fetal demise in both single and twin gestations. In addition to referral to genetics for counseling and consideration of diagnostic genetic testing, a detailed anatomic survey and fetal echocardiogram are indicated in the second trimester to screen for congenital malformations and major heart defects. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Prevalence and outcome of increased nuchal translucency in usmanu danfodiyo university teaching hospital, Sokoto, Nigeria: A cohort study

Background

An important component of the first-trimester scan is nuchal translucency thickness at 11 weeks to 13 weeks 6 days of gestation. A nuchal translucency ≥3.3 mm is a significant early pregnancy scan finding associated with Trisomies 13, 18, and 21 and congenital heart diseases.

Aims

To determine the prevalence and outcome of increased fetal nuchal translucency among pregnant women.

Subjects and Methods

A prospective cohort study at the Obstetrics and Gynaecology Department of Usmanu Danfodiyo University Teaching Hospital Sokoto. This was a prospective study of 265 consecutively recruited women in the first trimester of pregnancy who presented to antenatal clinics over a 20-week period. An NT scan was conducted at 11 weeks to 13 weeks 6 days followed by an anomaly scan at 18-22 weeks. Patients were followed up to delivery and 6-week post-partum. The neonates were examined at delivery and at 6-week postnatal life. Data entry and analysis was done with IBM SPSS version 20. The level of significance was set at less than 0.05. Frequency distribution; student t-test and Chi-squared test.

Results

The 95^th percentile NT was 3.3 mm and the prevalence of increased NT above 3.3 mm was 3%. The mean maternal age of the participants was 28.1 ± 5.1 years and the modal parity was Para 0. The most common anomalies associated with increased NT were ventricular septal defect and spina bifida. A congenital anomaly was significantly associated with increased NT (P < 0.001).

Conclusions

The prevalence of increased fetal nuchal translucency is relatively high in our environment and is associated with congenital fetal defects. Routine screening with first-trimester ultrasound will help detect congenital anomalies early.

Tetralogy of Fallot and Outlet Ventricular Septal Defect with Anterior Malalignment Detected at Early Fetal Echocardiography

OBJECTIVES

To examine the evolution of tetralogy of Fallot (TOF) and outlet ventricular septal defect (VSD) with anterior malalignment (am) from the initial diagnosis at early fetal echocardiography through the gestation and to evaluate the impact of the first-trimester scan on the outcome.

METHODS

We identified cases of TOF or outlet VSD with am diagnosed before 16 weeks' gestation. For all cases, prenatal data and pregnancy outcomes were evaluated. In continuing pregnancies, the evolution in severity of the disease was assessed.

RESULTS

Fifty-one fetuses with TOF or outlet VSD with am were diagnosed at early fetal echocardiography. Parents opted for termination of pregnancy in all 23 cases associated with additional anomalies. In 2 of 28 continuing pregnancies, there was an intrauterine death. In the remaining 26, there was progression in severity in 7 (by 20-22 weeks in 3 cases and during the third trimester in the remaining 4).

CONCLUSIONS

TOF and outlet VSD with am diagnosed before 16 weeks' gestation can progress in severity throughout pregnancy in over one-quarter of cases. In addition, a high proportion of cases diagnosed in the first trimester may have associated extracardiac anomalies, with a significant impact on clinical management and on the rate of early termination of pregnancy.

A risk model of prenatal screening markers in first trimester for predicting hypertensive disorders of pregnancy

Background

We aimed to construct a risk model to assess the diagnostic value of predicting hypertensive disorders of pregnancy (HDPs) by screening a range of prenatal markers, including pregnancy-associated plasma protein A (PAPP-A), free beta-human chorionic gonadotropin (free β-hCG), and fetal nuchal translucency (NT).

Method

We analyzed 902 women, classified into four groups: healthy gravidas (n = 680, controls), gravidas with gestational hypertension (n = 61; GH), gravidas with preeclampsia (n = 90; PE), and gravidas with severe preeclampsia (n = 71, SPE). We then compared the multiple of median (MoM) of PAPP-A, free β-hCG, and NT. A risk model was constructed and receiver operating characteristic curve (ROC) analysis was used to diagnose HDPs.

Results

Levels of PAPP-A and free β-hCG levels in the GH, PE, and SPE groups were significantly lower than those in the control group (χ ² = 7.522, P = 0.001; χ ² = 17.775, P < 0.001). NT did not differ significantly when compared across all four groups (χ ² = 1.592, P > 0.05). When the cut-off values for PAPP-A and free β-hCG were 0.795 MoM and 1.185 MoM, the corresponding sensitivities and specificities were 0.514 and 0.635, and 0.734 and 0.450, respectively. The best risk calculation featured PAPP-A, free β-hCG, and NT; this model exhibited the highest diagnostic value in the SPE group, followed by the GH group and then the PE group.

Conclusion

The use of prenatal screening markers during early pregnancy can identify fetal aneuploidy and can also predict HDPs. The development of innovative screening strategies for gravidas and the targeted prevention of HDPs in high-risk gravidas are essential for perinatal care and early intervention, thus creating significant opportunities for predictive and preventive personalized medicine. In our study, we found that the combination of a series of prenatal screening markers in early pregnancy is better than a single marker; our data clearly demonstrate the diagnostic value of combining PAPP-A, free β-hCG, and NT for patients with SPE.

Combination of "Markers" and the Consequent Importance of Fetal Abdominal Circumference in the First Trimester for Predicting Complications Specific to Monochorionic Twin Pregnancies

BACKGROUND

Multifetal pregnancies are considered high-risk pregnancies compared to singleton pregnancies. Monochorionic diamniotic (MCDA) twin pregnancies tend to have a more complicated intrauterine course than their dichorionic counterparts. The most common complications are twin-to-twin transfusion syndrome (TTTS), selective fetal growth restriction (sFGR), and unexplained intrauterine fetal demise (IUFD). Early recognition of pregnancies at risk of developing complications will be helpful for counselling the parents and preparing them for necessary interventions in case a complication arises.

OBJECTIVES

The aim of our study was to assess the role of discordant crown-rump length (dCRL), discordant nuchal translucency (dNT), and discordant abdominal circumference (dAC) measurements in isolation and in combination at the 11-13+6 weeks' scan in predicting the development of TTTS, sFGR, and IUFD.

METHODS

All MCDA twin pregnancies with structurally normal, both live fetuses at the 11-13+6 weeks' scan were followed up by FMF (Fetal Medicine Foundation)-certified operators for development of TTTS, sFGR, and single/double IUFD until delivery. Discordance of CRL, NT, and AC of more than or equal to 10% was considered a "marker," and its presence was correlated with the occurrence of specific antenatal complications, i.e., TTTS, sFGR, and single or double IUFD.

RESULTS

Combination of two markers predicted MCDA-related complications in the majority of cases (70.8% positive predictive value). Combination of dNT and dAC was the strongest predictor (80% positive predictive value).

CONCLUSIONS

In our population of MC twin pregnancies, dCRL, dNT, and dAC at the 11+0-13+6 weeks' scan, in isolation, had a low predictive value for antenatal complications, i.e., TTTS, sFGR, and single/double IUFD. However, the presence of at least two markers in the first trimester could predict complications in the majority of these pregnancies. The combination of dNT and dAC appears to be the best.

Prenatal and postnatal phenotype of a pathologic variant in the ATP6AP1 gene

INTRODUCTION

The ATP6AP1 gene encodes for ATPase H+ transporting protein. ATP6AP1 gene mutations are associated with congenital disorders of glycosylation (CDG) and can affect multiple organ system. Descriptions of postnatal phenotype include immunodeficiency, hepatopathy and cognitive impairment. No prenatal phenotype of these gene mutations has been described to date.

CASE

This is a description of the prenatal workup of an infant diagnosed with a X-linked ATP6AP1 gene mutation. First trimester ultrasound demonstrated a thickened nuchal translucency measured at 3.27 mm and dysmorphic spinal canal, corresponding to kyphoscoliosis finding postnatally. Findings from amniocentesis at 15 weeks included elevated amniotic fluid alpha-fetoprotein (AF-AFP) and positive acetylcholinesterase (AchE). Dilation of the aortic arch was seen on fetal echocardiogram at 20 weeks. Throughout the second trimester, a rim of fluid collection was seen under the skin covering the thoracic and lumbar fetal spine, consistent with a large Aplasia Cutis below the right scapula present at birth.

CONCLUSION

To our knowledge, this is the first description of prenatal phenotype of an X-linked ATP6AP1 gene mutation, and the association of this gene mutation with increased NT, elevated AF-AFP and AchE and Aplasia Cutis Congenita. This variant was submitted to ClinVar public database, submission ID: SUB6537411.

Genetic Examination for Fetuses with Increased Fetal Nuchal Translucency by Genomic Technology

This study aims to investigate the value of chromosomal microarray analysis (CMA) and whole exome sequencing (WES) in fetuses with increased nuchal translucency (defined as NT above the 95th centile for the crown-rump length). A total of 374 singleton pregnancies with gestational ages ranging from 11 to 13 + 6 weeks were investigated. Ultrasound displayed increased NT and no detectable structural malformations in these fetuses. Pregnancies were divided into 4 groups according to the NT values: 95th centile-3.4 mm (114 cases); 3.5-4.4 mm (150 cases); 4.5-5.4 mm (55 cases); and ≥5.5 mm (55 cases). The possible chromosomal anomalies were all analyzed by CMA first. Furthermore, 24 cases with increased NT but negative CMA results were investigated by WES, and the outcomes were followed up. Among all the 374 cases, causative genetic defects were detected in 100/374 (26.7%) of the cases along with 9 variants of unknown significance (VOUS) by CMA. CMA testing yielded 30 pathogenic variants (30/55), accounting for a detection rate of 54.5%, and 1 VOUS in the group of NT ≥5.5 mm, indicating the highest detection rate in the 4 groups. The 24 cases of the CMA negative sub-cohort with WES analysis further yielded 2 VOUS and 3 likely pathogenic variants, including 2 dominant de novo mutations in SOS1 and ECE1 and 1 recessive inherited compound heterozygous mutation in PIGN, which are associated with cardiac defects. All 3 cases opted for termination of pregnancy (TOP). In addition, 2 cases with increased NT were negative by both CMA and WES analysis, and fetal demise occurred. In conclusion, for the investigation of fetuses with increased NT exome sequencing is suggested to be considered in cases with negative CMA findings. However, appropriate genetic counseling should be given to optimizing its utilization in prenatal diagnosis.

Relationship between first trimester nuchal septations and chromosomal anomalies

OBJECTIVES

This study aimed to evaluate the association of nuchal septations with chromosomal anomalies during the first trimester of pregnancy.

METHODS

A total of 281 patients who were diagnosed to have elevated nuchal translucency (NT > 3 mm) or nuchal septations during the first trimester from Jan. 2014 to Dec. 2016 were included. These patients were divided into three groups: 1) patients with NT thickness between 3 and 5 mm and without nuchal septations (NT 3-5 mm group, n = 124), 2) patients with NT thickness > 5 mm and without nuchal septations (NT > 5 mm group, n = 96), and 3) patients with nuchal septations (NS group, n = 61).

RESULTS

The rate of chromosomal abnormalities was significantly higher for patients in NS group compared to those in the NT 3-5 mm group (P < .01) and NT > 5 mm group (P < .01). After controlling for maternal age, maternal BMI, ethnicity and crown-rump length, nuchal septations were reported to be significantly associated with a higher risk of chromosomal anomalies compared with NT 3-5 mm (OR = 4.97; 95% CI: 2.76-10.77; P < .01) and NT > 5 mm (OR = 3.82; 95% CI: 1.87-7.21; P < .01) (P < .01).

CONCLUSIONS

Measurement of nuchal septations during the first trimester of pregnancy proves to be a useful ultrasound prognostic indicator of chromosomal anomalies.

Pregnancy outcome in foetuses with increased nuchal translucency - 10-years' experience in a prenatal medical practice

This retrospective study describes pregnancy outcome for foetuses with increased nuchal translucency (NT) in relation to the degree of increase in a local specialised medical practice. Data from 7352 first trimester pregnancies examined by a single observer between 10/07 and 07/17 were screened. Three hundred and ninety-three foetuses (5.3%) that had an increased NT ≥ 95th percentile and available pregnancy outcome were identified. For this population, the frequencies of chromosomal abnormality, foetal malformation, intrauterine death (IUD) and termination of pregnancy (TOP) were determined in relation to the degree of NT thickness. Favourable pregnancy outcome decreased from 77.8% (lowest NT group, 95th percentile-3.5 mm) to 5% (highest NT ≥ 6.5 mm), whereas chromosomal abnormalities rose from 18.1% to 70%. An abnormal karyotype occurred in 39.2% of foetuses with increased NT. In euploid foetuses, cardiac defects were the most common structural abnormalities. The data largely matches with earlier studies conducted in large hospital-based settings. However, a rather high proportion of foetuses with abnormal karyotype was observed.IMPACT STATEMENTWhat is already known on this subject? Increased NT is associated with chromosomal abnormalities as well as an adverse perinatal outcome also in foetuses with a normal karyotype. The prevalence of an adverse outcome increases with NT thickness. These studies were conducted more than 10 years ago mainly in academic settings.What do the results of this study add? This study describes pregnancy outcome of a population of foetuses with increased NT that were examined in a medical practice by a single observer over a period of 10 years with state of the art ultrasound equipment. We observed a relatively large proportion of foetuses with abnormal karyotype. In euploid foetuses, increased NT was associated with a wide range of foetal malformations and genetic syndromes.What are the implications of these findings for clinical practice and/or further research? Even mildly increased NT thickness is associated with an adverse pregnancy outcome, underlining the importance of thorough ultrasound examinations. Specialised prenatal medical practices can provide state-of the art technology and provide improve parental counselling.

Increased nuchal translucency and pregnancy outcomes: experience of Başkent University Ankara Hospital

Objective:

First trimester nuchal translucency (NT) measurement is considered to be an important tool in antenatal follow-up. This study aimed to evaluate the outcomes of pregnancies with increased NT at Başkent University Ankara Hospital between 2004 and 2016.

Materials and Methods:

Patients with NT measurements ≥1.5 multiples of median (MoM) were divided into two groups; group I included increased NT cases without fetal anomalies (either abnormal fetal karyotype or congenital structural anomalies) or loss (intrauterine fetal death), and group II included increased NT cases with fetal anomalies or loss. The groups were compared with each other with respect to maternal demographic features and NT measurements.

Results:

Karyotype analyses were normal in 73.1% of cases with increased NT (57/78). Among those, 21.1% (12/57) had structural anomalies, and to specify, 9.6% (5/52 over 18 weeks) had cardiac anomalies. Although maternal demographic features did not differ significantly, NT measurements, both as millimeters and MoM, were significantly higher in group II (p<0.05). According to the receiver operating characteristic (ROC) curves, the optimal cut-off values for NT measurements for predicting fetal anomalies or loss were 3.05 mm and 2.02 MoM. NT measurement >7 millimeters or NT MoM >4.27 resulted in poor fetal outcomes without exception.

Conclusion:

Higher NT measurements indicate poorer pregnancy outcomes. Our study indicates that fetal echocardiography must be considered for all cases with increased NT.

Value of increased nuchal translucency in the era of noninvasive prenatal testing with cell-free DNA

OBJECTIVE

To assess the value of increased nuchal translucency (NT) at first-trimester screening (FTS) despite the superiority of noninvasive prenatal testing with cell-free DNA (cfDNA) for the detection of fetal aneuploidies.

METHODS

Retrospective analysis of all FTS data from 2005 to 2015 in our department. Only cases with increased NT and euploid karyotype were considered eligible for inclusion. Abnormal findings, diagnostic work-up, and perinatal outcomes were assessed.

RESULTS

Of 18 084 FTS results, 460 (2.5%) showed increased fetal NT, of which 242 (52.6%) underwent invasive karyotyping and 179 (74.0%) had an aneuploidy. Of the remaining 63 cases, 61 (96.8%) showed an additional sonographic finding at FTS and25 (78.1%) had a major anomaly at the second trimester organ scan. The outcome was termination of pregnancy in 28 (44.4%) cases, fetal demise in 5 (7.9%), delivery of an infant with malformation in 21 (33.3%), and delivery of a healthy infant in 7 (11.1%) cases.

CONCLUSION

All cases with increased NT would have been detected by cfDNA or by a major sonographic anomaly not later than the second trimester. Routine use of cfDNA, a basic sonogram, and an organ scan could reduce unnecessary work-up and anxiety.

Fetal nuchal translucency: is there an association with birthweight and neonatal wellbeing?

Objective

To evaluate the relationship between nuchal translucency (NT) values with birthweight and the wellbeing of the newborn.

Materials and Methods

This retrospective cohort study that included 508 patients made use of data on healthy full-term, singleton, live birth newborns in a university hospital between 2016 and 2018. The relationship between the NT multiple of the median (MoM) value and maternal body mass index, birthweight, sex, need for neonatal intensive care unit (NICU), and APGAR scores was evaluated. Similarly, the relationship between birthweight and NT MoM, and biochemical data in the first trimester was also evaluated.

Results

There was a positive correlation between NT and birthweight (p<0.001). The need for NICU admission increased (p=0.001), and APGAR 1st minute scores decreased (p=0.001) with increasing NT, and APGAR 5th minute scores remained unchanged (p=0.057).

Conclusion

The present study identified a positive correlation between first trimester NT and birthweight, and a negative correlation with the wellbeing of the neonate.

Cleft Palate with or without Cleft Lip: The Role of Retronasal Triangle View and Maxillary Gap at 11-14 Weeks

OBJECTIVE

To evaluate the presence of maxillary gap (MG) and abnormal retronasal triangle (RT) as markers of cleft palate (CP) with and without cleft lip in the first trimester and to assess their association with the type of orofacial cleft (OC).

METHODS

The RT and the mid-sagittal view of the face were evaluated retrospectively by two operators in 26 fetuses with OC and in 80 normal controls to detect abnormal RT and/or MG. The agreement between operators was calculated.

RESULTS

Amongst the 26 fetuses, there were 15 cases of bilateral, 6 cases of unilateral, and 4 cases of median cleft lip and palate, and 1 case of CP alone. The MG was observed in 18 cases by operator 1 and in 17 cases by operator 2; an abnormal RT was detected in 21 cases by operator 1 and in 22 cases by operator 2. Great agreement between operators was obtained. In controls, MG or abnormal RT was suspected in 6 and 2-4% of cases, respectively.

CONCLUSIONS

RT seems to be more sensitive compared to MG; however, the latter showed an additional diagnostic ability when the secondary palate was involved. Both approaches in combination could be useful in detecting OC in the first trimester.

Performance of Common Down Syndrome Screening Methods Used in India with Construction of an Indian Normogram for Nuchal Translucency/Crown-Rump Length Measurements in 14,337 Subjects

Background/Purpose of Study

Sonologists often lack access to the Fetal Medicine Foundation Down syndrome risk calculation software or cannot offer the combined test for aneuploidy screening because of resource constraints. Instead, sonologists use nuchal translucency (NT) measurements that rely on fixed NT cut-offs for labelling foetuses with high risks for Down syndrome. In the present study, we aimed to plot normative data for NT and the crown-rump length (CRL) in Indian foetuses and to assess the value of using the 95th/99th centiles of NT for CRL cut-offs instead of fixed NT cut-offs to calculate the risk for aneuploidies during the first trimester.

Methods

We conducted a retrospective observational study measuring the NT/CRL in 14,337 Indian foetuses between 11 and 13 + 6 weeks of gestation. We used regression analysis and calculated the 95th/99th centiles of NT distribution. We compared performances of NT > 95th/99th centiles and fixed NT cut-offs of 2.5- and 3.5-mm  as screening.

Results

The NT measurements increased with increasing CRL values. NT > 95th centile for a particular CRL for detecting all aneuploidies had the maximum sensitivity of 73.9% for a false positive rate (FPR) of 4.3%. Similar values for fixed cut-off > 2.5 mm were 63.0% FPR 3.7% (T21 68.2 FPR 3.8%) and for NT > 3.5 mm 36.9% FPR 0.43% (T21 36.5% FPR 0.5%).

Conclusion

A fixed NT cut-off point is not appropriate for the first trimester screening. The best sensitivity for assessing aneuploidies is achieved using the 95th centile, but the 99th centile achieves higher specificity for gestational age.

Noninvasive Approaches to Prenatal Diagnosis: Historical Perspective and Future Directions

The field of prenatal screening and diagnosis has undergone enormous progress over the past four decades. Most of this period has been characterized by gradual improvements in the technical and public health aspects of prenatal screening for Down syndrome. Compared to the direct analysis of fetal cells from amniocentesis or chorionic villus sampling, noninvasive approaches using maternal blood or ultrasound have the great advantage of posing no risk of miscarriage to the pregnancy. Recent advances in molecular genetics and DNA sequencing have revolutionized both the accuracy and the range of noninvasive testing for genetic abnormalities using cell-free DNA in maternal plasma. Many of these advances have already been incorporated into clinical care, including diagnosis of fetal blood group and aneuploidy screening. The accelerated pace of these recent developments is creating not just technical and logistical challenges, but is also magnifying the ethical and public policy issues traditionally associated with this field.

False-positive rates in screening for trisomies 18 and 13: a comparison between first-trimester combined screening and a cfDNA-based approach

PURPOSE

To determine the false-positive rates (FPR) associated with screening for trisomy 18/13 using first-trimester combined screening (FTCS) and an ultrasound plus cfDNA-based approach (US-cfDNA), which includes a detailed ultrasound examination, a cfDNA analysis and a FTCS reflex backup test for cases with uninformative results.

METHODS

This is a sub-analysis of a randomized controlled trial, which was performed between 2015 and 2016. Pregnant women with a normal first-trimester ultrasound examination at 11-13 weeks' gestation (NT < 3.5 mm, no anomalies) were randomized into two groups: FTCS and US-cfDNA screening. The overall FPR in screening for trisomies 18/13 and 21 was compared with the FPR in screening for trisomy 21 alone. Pregnancies were considered screen positive if the risk for trisomy 21 was 1:100 and for trisomy 18 and 13, 1:20 each.

RESULTS

The study population consisted of 688 pregnancies in each study arm. In the FCTS group, median delta NT was 0.0 mm, free beta-hCG and PAPP-A 0.96 and 1.11 MoM. In the US-cfDNA group, median delta NT was 0.0 mm. In 10 pregnancies, the cfDNA analysis was uninformative. In the FTCS and in the US-cfDNA group, the FPR in screening for trisomy 21 was 2.5% and 0%. In both groups, the overall FPR was not increased by adding screening algorithms for trisomies 18 and 13.

CONCLUSION

In conclusion, the addition of screening for trisomies 18 and 13 to screening for trisomy 21 does not significantly change FPR. This is true for both the FTCS and the US-cfDNA-based approach.

Prenatal diagnosis of Down syndrome: A 13-year retrospective study

OBJECTIVE

The aim of this study is to summarize the experience on prenatal diagnosis of Down syndrome.

MATERIALS AND METHODS

The study includes a retrospective data analysis of 157 prenatally detected cases of Down syndrome, routinely diagnosed among 6448 prenatal investigations performed during a 13-year period (2002-2014) in a single tertiary center.

RESULTS

The prevalence of diagnosed Down syndrome cases was 2.4%. Maternal age alone was indication for prenatal diagnosis in 47 cases (45.2%), increased first-/second-trimester biochemical screening test in 34 cases (21.7%), abnormal ultrasound examination in 69 cases (43.9%), positive familial history for chromosomal abnormalities in four cases, and high risk for trisomy 21 revealed by cell-free DNA testing in three cases. Ultrasound anomalies were present in total of 94 fetuses (59.8%). The most common abnormality was cystic hygroma found in 46 cases (29.3%). A regular form of Down syndrome (trisomy 21) was found in 147 cases (93.6%), Robertsonian translocation in six cases (3.8%), and mosaic form in four cases (2.6%).

CONCLUSION

In prenatal diagnosis of Down syndrome noninvasive screening methods are important for estimation of individual risks, in both, young population of woman and older mothers, while conventional and molecular cytogenetic methods are essential for definite diagnosis and proper genetic counseling.

Association between unexplained thickened nuchal translucency and adverse pregnancy outcomes

OBJECTIVE

To determine the association between unexplained increased nuchal translucency (INT) and adverse pregnancy outcomes.

PATIENTS AND METHODS

The prospective database of our fetal down screening project was accessed to retrieve the records with NT measurement and complete follow-up. Pregnancies with pre-existing medical diseases, fetal chromosomal or structural abnormalities were excluded. The selected pregnancies were classified into the INT groups (> 95th percentile), the normal (< 95th percentile) group.

RESULTS

Of 6026 available for analysis (INT:277; and normal: 5749), the abortion rate was significantly higher in the INT group, 18/277 (6.5%) versus 55/5749 (1.0%); p < 0.001. After excluding 73 cases ending-up with abortion, a total of 5953 women were analyzed for final pregnancy outcomes, including 260 (4.4%), and 5693 (95.6%) in the study group (INT), and the control group (normal NT), respectively. The rates of pre-eclampsia (7.3 vs. 4.1%; p: 0.018), preterm birth (12.7 vs. 8.4%; p: 0.023), fetal growth restriction (11.5 vs. 7.6%; p: 0.032), and low birth weight (16.5 vs. 10.0%; p: 0.002) were slightly, but significantly higher in the study group.

CONCLUSIONS

INT in the first trimester is associated with significantly increased risk of abortion, fetal growth restriction, preterm birth, low birth weight and pre-eclampsia.

Isolated Cleft Lip and Palate: Maxillary Gap Sign and Palatino-Maxillary Diameter at 11-13 Weeks

OBJECTIVE

To evaluate the maxillary gap sign and describe markers for the first-trimester diagnosis of isolated cleft lip and palate (CLP) at 11-13 weeks.

METHODS

Firstly, this was a prospective assessment of 1,087 fetuses including 5 cases of isolated CLP in 2 centers which were referred for the 11-13 weeks scan. Secondly, intra- and interobserver variability of the maxillary gap sign was evaluated for observers R.L. and A.B. in 2 sessions (affected cases vs. 50 normal fetuses in each session) to reduce the bias of different ultrasound manufacturer visualizations (Philips, GE). Thirdly, the palatino-maxillary diameter (PMD) was examined in stored images, DICOM loops and volumes of the midsagittal and parasagittal view of the fetal head and brain at 11+0-13+6 weeks of gestation from 5 fetuses with isolated CLP and 302 consecutively assessed normal controls. The PMD values in fetuses with isolated CLP and normal controls were compared.

RESULTS

Firstly, 5 out of 6 referred pregnancies with isolated CLP were detected prospectively using the midsagittal view for measurement of nuchal translucency due to an abnormal appearance. One out of 6 patients with isolated CLP declined the 11-13 weeks scan. Secondly, intra- and interobserver variability showed no false positive cases; all cases with isolated CLP were identified by both sonographers; however, in 2 cases the maxillary gap sign was doubtful. Therefore, thirdly, we developed the PMD measurement which increased significantly with crown-rump length (CRL) from respective mean values at CRL of 45 mm to 4.66 mm and to 8.95 mm at CRL of 84 mm. In the CLP group, the PMD was below the 5th percentile of the control group in 4 out of 5 (80%) cases.

CONCLUSIONS

The midsagittal view for measurement of nuchal translucency shows a high reproducibility regarding abnormal views for maxillary gap sign. In the midsagittal view of the fetal head, face, and brain at 11-13 weeks, the majority of fetuses with isolated CLP have a measurable abnormality in addition, the PMD.

Principles of first trimester screening in the age of non-invasive prenatal diagnosis: screening for chromosomal abnormalities

PURPOSE

First trimester risk assessment for chromosomal abnormalities plays a major role in the contemporary pregnancy care. It has evolved significantly since its introduction in the 1990s, when it essentially consisted of just the nuchal translucency measurement. Today, it involves the measurement of several biophysical and biochemical markers and it is often combined with a cell-free DNA (cfDNA) analysis as a secondary test.

METHODS

A search of the Medline and Embase databases was done looking for articles about first trimester aneuploidy screening. We performed a detailed review of the literature to evaluate the screening tests currently available and their respective test performance.

RESULTS

Combined screening for trisomy 21 based on maternal age, fetal NT, and the serum markers free beta-hCG and PAPP-A results in a detection rate of about 90% for a false positive of 3-5%. With the addition of further ultrasound markers, the false positive rate can be roughly halved. Screening based on cfDNA identifies about 99% of the affected fetuses for a false positive rate of 0.1%. However, there is a test failure rate of about 2%. The ideal combination between combined and cfDNA screening is still under discussion. Currently, a contingent screening policy seems most favorable where combined screening is offered for everyone and cfDNA analysis only for those with a borderline risk result after combined screening.

CONCLUSION

Significant advances in screening for trisomy 21 have been made over the past 2 decades. Contemporary screening policies can detect for more than 95% of affected fetuses for false positive rate of less than 3%.

Observational study comparing the performance of first-trimester screening protocols for detecting trisomy 21 in a North Indian population

OBJECTIVE

To evaluate first-trimester screening protocols for detecting trisomy 21 in an Indian population.

METHODS

The present prospective study collected data from women with singleton pregnancies and a crown-to-rump length of 45-84 mm who presented at the fetal medicine unit of a tertiary care center in North India between June 1, 2006, and December 31, 2015, for combined first-trimester screening. Maternal age, nuchal translucency, nasal bone, and maternal serum levels of free beta human chorionic gonadotropin and pregnancy-associated plasma protein A were assessed for calculating the risk of trisomy 21. Tricuspid regurgitation and qualitative analysis of ductus venosus data were available from June 2010, and were included where available. Trisomy-21 detection rates were calculated for various screening protocols and were compared.

RESULTS

There were 4523 women screened and 24 records of trisomy 21. Combined screening with maternal age, nuchal translucency, nasal bone, tricuspid regurgitation, and ductus venosus demonstrated optimal detection and false-positive rates of 93.8% and 1.9%, respectively. Screening using only maternal age yielded a detection rate of 37.5%; using fixed nuchal translucency cut-off values of 2.5 and 3 mm resulted in detection rates of 66.7% and 37.5%, respectively.

CONCLUSION

Combined first-trimester screening performed well in an Indian population; combining maternal age, nuchal translucency, nasal bone, ductus venosus, and tricuspid regurgitation yielded the most accurate screening.

Automatic detection and measurement of nuchal translucency

In this paper we propose a new methodology to support the physician both to identify automatically the nuchal region and to obtain a correct thickness measurement of the nuchal translucency. The thickness of the nuchal translucency is one of the main markers for screening of chromosomal defects such as trisomy 13, 18 and 21. Its measurement is performed during ultrasound scanning in the first trimester of pregnancy. The proposed methodology is mainly based on wavelet and multi resolution analysis. The performance of our method was analysed on 382 random frames, representing mid-sagittal sections, uniformly extracted from real clinical ultrasound videos of 12 patients. According to the ground-truth provided by an expert physician, we obtained a true positive rate equal to 99.95% with respect to the nuchal region detection and about 64% of measurements present an error equal to 1 pixel (which corresponds to 0.1mm), respectively.

Enlarged NT (≥3.5 mm) in the first trimester - not all chromosome aberrations can be detected by NIPT

BACKGROUND

Since non-invasive prenatal testing (NIPT) in maternal blood became available, we evaluated which chromosome aberrations found in our cohort of fetuses with an enlarged NT in the first trimester of pregnancy (tested with SNP microarray) could be detected by NIPT as well.

METHOD

362 fetuses were referred for cytogenetic testing due to an enlarged NT (≥3.5 mm). Chromosome aberrations were investigated using QF-PCR, karyotyping and whole genome SNP array.

RESULTS

After invasive testing a chromosomal abnormality was detected in 137/362 (38 %) fetuses. 100/362 (28 %) cases concerned trisomy 21, 18 or 13, 25/362 (7 %) an aneuploidy of sex chromosomes and 3/362 (0.8 %) triploidy. In 6/362 (1.6 %) a pathogenic structural unbalanced chromosome aberration was seen and in 3/362 (0.8 %) a susceptibility locus for neurodevelopmental disorders was found. We estimated that in 2-10 % of fetuses with enlarged NT a chromosome aberration would be missed by current NIPT approaches.

CONCLUSION

Based on our cohort of fetuses with enlarged NT we may conclude that NIPT, depending on the approach, will miss chromosome aberrations in a significant percentage of pregnancies. Moreover all abnormal NIPT results require confirmatory studies with invasive testing, which will delay definitive diagnosis in ca. 30 % of patients. These figures are important for pretest counseling enabling pregnant women to make informed choices on the prenatal test. Larger cohorts of fetuses with an enlarged NT should be investigated to assess the additional diagnostic value of high resolution array testing for this indication.

Long-term outcome in apparently healthy children with increased nuchal translucency in the first trimester screening

INTRODUCTION

Increased nuchal translucency is known to be associated with chromosomal and structural defects and genetic syndromes. Little is known about the overall long-term outcome of euploid children after increased nuchal translucency. The aims of this study were to assess the additional structural defects diagnosed after discharge from the delivery hospital and the long-term overall outcome of euploid children after increased nuchal translucency and normal second trimester anomaly scan.

MATERIAL AND METHODS

All children from singleton euploid pregnancies during 2002-2007 with increased nuchal translucency in the first trimester screening, normal second trimester anomaly scan, and discharged as apparently healthy were included. Data on the structural defects and genetic disorders diagnosed until 2012 were retrieved from hospital databases and national registers. Previously published data of structural defects diagnosed after birth but before discharge and of severe neurodevelopmental impairment and genetic syndromes was added.

RESULTS

The cohort included 733 children. During the follow-up time (mean 6.5 years), major structural defects were observed in 10 (1.4%), genetic disorders in two (0.3%), and minor defects in 23 (3.1%) children. In addition, there were 42 previously published major structural defects and major neurodevelopmental impairment or genetic disorders. Adding these results together, major health problems were detected in 54 (7%) euploid children with increased fetal nuchal translucency and normal findings in second trimester anomaly scan.

CONCLUSION

Although only few additional major structural defects are diagnosed during the follow-up after increased fetal nuchal translucency, 7% of fetuses assumed to be healthy after second trimester anomaly scan have a major health impairment.

Noninvasive prenatal testing for fetal trisomy in a mixed risk factors pregnancy population

OBJECTIVE

This study assesses the performance of noninvasive prenatal testing (NIPT) for fetal aneuploidies in a mixed risk factors pregnancy population.

MATERIALS AND METHODS

Data review of 169 pregnant women undergoing prenatal aneuploidy screening in a single tertiary medical center was conducted. Indications included maternal anxiety, advanced maternal age, abnormal nuchal translucency, and high/moderate risk of first trimester Down syndrome screening. Multifetal pregnancies and patients receiving in vitro fertilization were also enrolled for analysis.

RESULTS

A total of 169 patients were enrolled in this study during a time period from July 2012 to June 2014. For patients' ≥ 34 years, anxiety about amniocentesis was the most common reason for patients selecting NIPT for fetal aneuploidy screening, with 107 (88.4%) patients choosing NIPT for this reason. Among the total patient population, two patients showed a positive result from NIPT. One patient displayed 47, XXY, which was confirmed to be a false-positive result. The other patient displayed trisomy 18, which was confirmed by an amniotic cell culture. The sensitivity for NIPT is 100% with the specificity 99.4%.

CONCLUSIONS

NIPT for fetal aneuploidy in a mixed risk factors pregnancy population showed high accuracy. NIPT applied to the low risk population might reassure the anxious family.

[First trimester screening for Down syndrome at Prima facie. A 6-year survey]

OBJECTIVE

To evaluate the results of screening for trisomy 21 by the combined risk of first trimester (as defined by the decree of June 23, 2009) in the Prima facie structure.

METHODS

Single center study involving all patients that were seen for first trimester screening at Prima facie with singleton living pregnancy, not obtained by embryo donation, between 1 January 2009 and 31 December 2014.

RESULTS

Eighteen thousand two hundred and fifty-one patients were included, of which underwent screening for trisomy 21 by the combined risk. One thousand and forty-six (6.1%) had a calculated risk higher than 1/250. Seventy-five were affected by trisomy 21, of whom 65 in the high risk group. The sensitivity and specificity of screening are 86.7% and 94.4%. The median nuchal translucency was 0.98 MoM.

CONCLUSIONS

Screening for trisomy 21 by calculating the combined risk of first trimester enabled to detect 86.7% of trisomy 21 with a false positive rate of 5.6%.

Prenatal diagnosis of fetuses with increased nuchal translucency using an approach based on quantitative fluorescent polymerase chain reaction and genomic microarray

OBJECTIVE

To assess the clinical value of prenatal diagnosis of fetuses with increased nuchal translucency (NT) using an approach based on quantitative fluorescent polymerase chain reaction (QF-PCR) and chromosomal microarray (CMA).

STUDY DESIGN

From January 2013 to October 2014, we included 175 pregnancies with fetal NT ≥ 3.5mm at 11-13 weeks' gestation who received chorionic villus sampling. QF-PCR was first used to rapidly detect common aneuploidies. The cases with a normal QF-PCR result were analyzed by CMA.

RESULTS

Of the 175 cases, common aneuploidies were detected by QF-PCR in 53 (30.2%) cases (30 cases of trisomy 21, 12 cases of monosomy X, 7 cases of trisomy 18, 3 cases of trisomy 13 and 1 case of 47, XXY). Among the 122 cases with a normal QF-PCR result, microarray detected additional pathogenic copy number variants (CNVs) in 5.7% (7/122) of cases. Four cases would have expected to be detectable by conventional karyotyping because of large deletions/duplications (>10 Mb), leaving three cases (2.5%; 3/118) with pathogenic CNVs only detectable by CMA.

CONCLUSION

It is rational to use a diagnostic strategy in which CMA is preceded by the less expensive, rapid, QF-PCR to detect common aneuploidies. CMA allows detection of a number of pathogenic chromosomal aberrations in fetuses with a high NT.

Uncommon Presentation of Triploidy: A Case Report

A 28-year-old woman presented in her first pregnancy was admitted with severe hyperemesis gravidarium. Increased nuchal translucency with cardiac anomaly and omphalocele at the first trimester was observed at the ultrasound examination. Chorionic villus biopsy confirmed triploidy. The combination of type I and type II triploidy patterns were seen together in the second trimester of the pregnancy. Although the symptoms due to increased human chorionic levels occured, at the pathologic investigation there were no molar changes in the placenta. Here we report a case of uncommon presentation of triploidy.

[A simple self-assessment tool for the first-trimester ultrasound images]

OBJECTIVES

The objective of this study was to establish a minimum subset of simple criteria for the self-assessment of the quality of first-trimester ultrasound images of nuchal translucency (NT) and crown-rump length (CRL).

METHODS

We designed 162 simplified image-scoring methods (ISM) based on 1, 2, 3 or 4 binary criteria derived from the 8 criteria of the original image scoring method of the French College of Fetal Ultrasound (CFEF). These ISM were assessed on 68,250 consecutive scans of the French national audit conducted by the CFEF on NT and CRL images. The ISM associated with the best precision to identify excellent/reasonable quality scans were selected.

RESULTS

Simplified ISM based on 1, 2, 3 and 4 criteria showed maximum positive predictive values of 95.3% (95.11-95.50) 98.0% (97.87-98.14), 99.3% (99.17-99.35) and 99.7% (99.68-99.79), respectively, to identify excellent/reasonable quality scans. The proportion of excellent/reasonable scans was 2.8 to 16.7% when three criteria among the 8 were insufficient, and 0.17 to 3.95% when four criteria were insufficient.

CONCLUSIONS

The best performing ISM was based on the following four quality criteria: (i) sagittal plane of the NT, (ii) calipers placement for measuring the NT, (iii) image magnification of NT images and (iv) CRL measurement. This score might be the most relevant in clinical practice in the first-trimester screening.