Hueso nasal, espesor prenasal, distancia esfeno-frontal y relación espesor prenasal/ hueso nasal fetal en el segundo trimestre de la gestación

Abstract

Objective: To identify the relationship between anatomical parameters considered as markers of chromosomal abnormalities: nasal bone length, prenasal thickness, spheno-frontal distance and to identify the prenasal thickness/nasal bone relationship; as well as, make normality tables. Method: Cross -sectional study performed from January 2017 to July 2018, measuring nasal bone length, prenasal thickness, sphenofrontal distance and the prenasal thickness/nasal bone ratio, with a non-probabilistic and intentional sample, made up of 325 patients between 18 and 24 weeks of gestation who met the inclusion criteria to perform their respective nomograms of the aforementioned structures. Results: Nasal bone length at 18 weeks 5.66 ± 0.80 days and 8.06 ± 0.76 days at 24 weeks (95 % CI 5.46 -8.51), mean nasal thickness 2. , the sphenofrontal distance fluctuated in values and the prenasal thickness/nasal bone ratio at 18 weeks was 0.53 ± 0.09 and 0.52 ± 0.11 at 24 weeks (95 % CI 0.37 -0.68). Conclusion:The phenotypic expression of the fetal profile may have subtle variations that mask the diagnosis of chromosomal abnormalities; Nasal bone length, prenasal thickness, and spheno-frontal distance were positively correlated with gestational age, while the prenasal thickness/nasal bone ratio decreased.