Association of Fetal Nasal Bone Length And Gestational Age Between 14-28 Weeks of Pregnancy

Nasal bone (NB) is a significant structure to be assessed during pregnancy in 1st and 2nd trimesters. Nasal bones that start to grow as neural crest cells (NCCs) collections, can histologically be confirmed when length of fetal crown–ump is 42mm (10.9 weeks).

Chromosomal Microarray Analysis of Fetuses with Nasal Bone Anomaly

Objective: To explore the significance and value of fetal nasal bone anomaly (absence or hypoplasia) as indications of prenatal diagnosis.Methods: A total of 102 fetuses diagnosed with nasal bone absence or hypoplasia by ultrasonography underwent chorionic, amniotic, or umbilical cord blood puncture. Single nucleotide polymorphism microarray (SNP-array) was used to analyze fetal chromosomes.Results: Of the 102 fetuses with nasal bone absence or hypoplasia, 25 (24.5%) had chromosomal abnormalities, including 15 cases of trisomy 21, one trisomy 18 case, and 9 cases of other copy number variations. Among the 52 cases with isolated nasal bone absence or hypoplasia, 7(13.5%) had chromosomal abnormalities. In 50 cases, abnormal nasal bone with additional soft markers or structural abnormalities was observed, while 18 cases (36.0%) had chromosomal abnormalities, which were significantly higher than that among the fetuses with isolated nasal bone abnormality.Conclusion: Fetal nasal bone absence or hypoplasia can be used as an indication for prenatal diagnosis. The detection rate of chromosomal abnormalities increases with additional soft markers or structural abnormalities. This study demonstrates that fetal nasal bone absence or hypoplasia is associated with micro-deletions or micro-duplications of chromosomes. Application of single nucleotide polymorphism microarray (SNP-array) technology can reduce the rate of missed prenatal diagnoses.