Absence Of Fetal Nasal Bone Research Articles

Is Noninvasive Prenatal Screening Appropriate for Pregnant Women Age 35 or Older In Cases if Isolated Fetal Nasal Bone Abnormalities in The Chinese Han Population?

BackgroundEthnic background may affect the prevalence of nasal bone absence and the length of the nasal bone. This study aimed to elucidate the significance of absent or hypoplastic fetal nasal bone in the Chinese Han population and to formulate an optimal management plan for patients age 35 or older in cases of isolated abnormal fetal nasal bone.Material/MethodsWe prospectively assigned pregnant women whose fetuses had nasal bone absence or hypoplasia to separate groups according to their choice for noninvasive prenatal screening (NIPS) between January 1, 2013, and December 31, 2018. Demographic data, ultrasound findings, results of conventional maternal serum screening and NIPS, fetal karyotype, pregnancy outcomes, and expenses associated with prenatal testing were recorded. The incidence and odds ratio of nasal bone abnormality and the sensitivity and specificity of different prenatal genetic screening tests were calculated.ResultsA total of 1946 cases with fetal nasal bone absence or hypoplasia were included. Cases of isolated nasal bone abnormality (1736 cases) were divided into the NIPS group (Gr 1, n=429) and the non-NIPS group (Gr 2, n=1307). Sixty-four cases involved chromosomal abnormality. The sensitivity, specificity, and positive and negative predictive values of NIPS in Gr 1 were 100%, 100%, 100%, and 100%, respectively. The odds ratio of fetal chromosomal abnormalities for isolated fetal nasal bone abnormalities when maternal age was ≥35 was 4.615 (95% CI: 1.592–13.381). The cost-effectiveness ratio of contingent screening (NIPS first) was significantly lower than amniocentesis directly.ConclusionsThe nasal bone provides an important marker for chromosome abnormalities in some populations, but to a lesser extent in the Chinese Han population. NIPS is an excellent first option for follow-up among pregnant women age ≥35 in cases of absent or hypoplastic fetal nasal bone in the first trimester ultrasound scan.

Application of chromosomal analysis for 29 cases of fetuses with nasal bone absence or hypoplasia

Objectives: To explore the chromosomal analysis for fetuses with nasal bone absence or hypoplasia. Methods: This was a retrospective study on 29 pregnancies nasal bone absence or hypoplasia which underwent prenatal diagnosis, including chorionic villi (CV), amniotic fluid or cordocentesis.The indication of the procedures and results were evaluated. Result: Fifteen (51.7%, 15/29) of chromosome abnormities were diagnosed with indication of fetal nasal bone absence or hypoplasia, including eight with trisomy 21, two with trisomy 13, two with X chromosome aneuploidy and three with pathogenic copy number variations (CNVs) respectively.The incidence of chromosomal abnormalities in fetus with nasal bone hypoplasia (2/5, 40%) was lower than that in fetus with nasal bone absence (13/29, 54.2%). The incidence of chromosomal abnormalities in fetus with non-syndromic nasal bone absence or hypoplasia (4/13) was lower than that in fetus with syndromic nasal bone absence or hypoplasia (11/16). Conclusion: The incidence of chromosomal abnormalities in fetus with nasal bone absence or hypoplasia was higher and prenatal diagnosis was recommended for all types of the disease.For the fetus with nasal bone absence or hypoplasia, it is recommended to give priority to CNVs for prenatal diagnosis.

“First Things First”: Fetal Nasal Bone Imaging in the First Trimester 11–13+6 Weeks Scan

AbstractThe first trimester scan is an important tool of risk assessment for fetal aneuploidies. The presence or absence of fetal nasal bone is an important secondary marker for risk allocation. This article describes the method of obtaining an ideal image for assessment of fetal nasal bone during the 11–13+6 weeks scan.

Avaliação ultra-sonográfica do osso nasal fetal: evolução das medidas ao longo da gestação

PURPOSE: the absence of fetal nasal bone is correlated with trisomy 21. Although a hypoplastic nasal bone is also correlated with trisomy 21, there is no clear definition of this term in the literature. Our objective was to establish the reference values for fetal nasal bone size throughout gestation in a local population in Brazil. METHODS: it is a cross-sectional study on 902 fetuses at 10 to 39 weeks of gestation. After having excluded fetal malformations and maternal diseases which are known to interfere with fetal growth, 625 fetuses were selected. We obtained a mid-sagittal view of the fetal profile by holding the ultrasound bean at an angle of 45o or 135o. The nasal bone size mean was calculated by using polynomial regression. The Anderson-Darling test proved the normal distribution of the measurements (p>0.05). RESULTS: of the 625 fetuses, 88.3% were from single gestations and 11.7% from multiple ones. There was a direct correlation between fetal nasal bone size and gestational age. The variability of nasal bone size became larger as gestational age increased. Minimal length of 1.0 and 4.7 mm in the first and second trimesters, respectively, were found. CONCLUSIONS: there is a direct correlation between fetal nasal bone size and gestational age. This correlation is valid either for a single gestation or a multiple one. These measurements of the fetal nasal bone will allow us to use them as a screening test for cromosomal abnormalities. This is a useful study if we consider the large miscegenation of the Brazilian population. However, further systematic and standardized approach to study the fetal nasal bone is needed to establish its real value in fetuses once classified as at high or low risk for aneuploidies.

Additional Performance of Nasal Bone in First Trimester Screening

To evaluate and compare the screening performance for fetal trisomy 21 in the first trimester of pregnancy either with or without inclusion of fetal nasal bone using two separate risk-algorithms of the Fetal Medicine Foundation London (FMF). This study included 3174 patients self-referred to our tertiary level prenatal centre for first trimester screening at 11-14 weeks of gestation between December 1, 2002 and November 30, 2004. Fetal risk for trisomy 21 was calculated using either the old FMF-algorithm including maternal age, nuchal translucency (NT), free ss-human chorionic gonadotropin (hCG), pregnancy-associated plasma protein-A (PAPP-A) or the new FMF-algorithm using additionally the presence or absence of fetal nasal bone (NB). All ultrasonographers were certified for measurement of nuchal translucency and nasal bone by the Fetal Medicine Foundation Germany. The detection rate for a fixed risk cut-off (1:300) and a fixed false-positive rate (5 %) was calculated for ultrasound (single NT or NT and NB), serum biochemistry, maternal age and the combination of these components. Pregnancy outcome was obtained in 2973 (93.6 %) cases. Nasal bone was absent in 5 of 18 (27.8 %) cases with fetal trisomy 21 and in 2 of 2961 (0.1 %) normal cases. The estimated risks for trisomy 21 based on maternal age, fetal ultrasound and maternal serum free ss-hCG and PAPP-A was 1 in 300 or greater in (old algorithm without NB/new algorithm including NB) 5.5 % (179 of 2961) and 2.8 % (97 of 2961) normal pregnancies and in 94.4 % (17 of 18) and 77.8 % (14 of 18) of those with trisomy 21. For a fixed false-positive rate of 5 % the respective detection rates of screening for fetal Down's syndrome by maternal age and serum free ss-hCG and PAAP-A, maternal age and fetal ultrasound and by maternal age, fetal ultrasound and maternal serum biochemistry were (old algorithm without NB/new algorithm including NB) 72.2 %/66.7 %, 83.3 %/77.8 % and 88.9 %/83.3 %, respectively. Our data show no additional performance of including presence or absence of fetal nasal bone in calculation of risk for fetal Down's syndrome between 11 and 14 weeks of gestation. Individual risk-orientated two-stage screening could be an alternative approach for integration of additional ultrasound markers in first trimester screening.

Fetal nasal bone and trisomy 21 in the second trimester

To assess the feasibility of measuring nasal bone length in the second trimester of pregnancy and to confirm if fetal nasal bone absence or hypoplasia is a marker for Down syndrome. Fetal nasal bone assessment was performed in 439 consecutive singleton pregnancies at high risk of Down syndrome between 15 and 21 weeks. All ultrasound examinations were performed transabdominally by five skilled sonographers. If the nasal bone was present, its length was measured. The biparietal diameter: nasal bone length ratio (BPD/NBL) was also calculated. Nasal bone assessment was successfully achieved in all fetuses. The nasal bone was absent in 2(0.47%) of the 417 unaffected fetuses and in 10(55.5%) of the 18 fetuses with trisomy 21. Of the 8 Down syndrome cases with a nasal bone present, 4 had nasal bone hypoplasia and 4 had a normal nasal bone. BPD/NBL was 9 or greater in 7 of the 8 fetuses affected by trisomy 21 with nasal bone present and in 86 (20.6%) of the 417 normal fetuses; it was 10 or greater in 5 of the 8 (62.5%) fetuses affected by trisomy 21 and in 41 of the 417 (9.8%) euploid fetuses. Nasal bone absence is a marker for Down syndrome in the second trimester of pregnancy. Inclusion of nasal bone length into the second-trimester screening protocol could potentially obviate the false-negative cases from other screening tests. The measurement of nasal bone length in the second trimester seems to provide additional benefits beyond the assessment of the presence or absence of the nasal bone.

Absence of fetal nasal bone and aneuploidies at first-trimester nuchal translucency screening in unselected pregnancies.

The absence of nasal bone (NB) has been noted in trisomy 21 fetuses at first-trimester ultrasound, in high-risk pregnancies. In this study, the nasal bone was evaluated in relation to fetal karyotype, in unselected pregnancies. From September 2001 to September 2002, the fetal facial profile was examined at the 11 to 14 weeks' scan for screening by nuchal translucency (NT). Risks for trisomy 21 were calculated using the Fetal Medicine Foundation's software, and the presence or absence of NB was noted. Prenatal karyotype and pregnancy outcomes were recorded. NT screening was performed in 5532 fetuses from 5425 pregnancies (85 twins, 8 triplets, 2 quadruplets). The visualization of fetal profile was obtained in 5525 fetuses (99.8%), and in 5491 fetuses (99.4%) the NB was present and in 34 cases (0.6%) it was absent. Fetal karyotype and pregnancy outcome were available in 3503 pregnancies, and 40 chromosomal abnormalities were diagnosed (27 trisomies 21, 5 trisomies 18, 2 trisomies 13, 3 Turner syndromes, 1 partial trisomy 9 and 2 others). The NB was absent in 19 (70%) trisomies 21, 4 trisomies 18 (80%), 2 Turner syndromes (66%), in the partial trisomy 9, in 7 normal karyotype fetuses (0.2%), and in a case with spontaneous first-trimester abortion before prenatal diagnosis. A significant difference was found between NT thickness, expressed as a multiple of the median, in trisomy 21 fetuses with present and absent nasal bone. The absence of NB at 11 to 14 weeks is more frequent in fetuses with trisomy 21 and other aneuploidies than in normal karyotype fetuses.

Association between first trimester absence of fetal nasal bone on ultrasound and Down syndrome

To evaluate the association between absence of nasal bone on ultrasound and Down syndrome in fetuses at 11-14 weeks of pregnancy. One hundred and ninety-four consecutive fetuses from singleton pregnancies undergoing chorionic villi sampling (CVS) were evaluated by transabdominal ultrasound. A sagittal view of the fetal face was obtained and the absence or presence of nasal bone was recorded and correlated with the fetal karyotype. A successful view of the fetal profile was possible in 183 of 194 (94%) fetuses. The nasal bone was absent in three of five fetuses with Down syndrome, and in one of 175 (0.6%) chromosomally normal fetuses. Absence of nasal bone by first trimester ultrasound was significantly associated with Down syndrome. When a proper view of the fetal face was obtained, the nasal bone was visible in more than 99% of karyotypically normal fetuses.