Alfredo J. Cervantes-Ricaud, Departamento de Ginecología y Obstetricia, Hospital Español, Sociedad de Beneficencia Española, Ciudad de México, México
Héctor Oviedo-Cruz, Departamento de Diagnóstico y Terapia Fetal, Centro Médico para Atención Fetal Especializada; Departamento de Educación e Investigación, Laboratorio, Centro Médico para Atención Fetal Especializada. Ciudad de México, México
Background: The standardized assessment of the hypoplastic nasal bone (NB) by ultrasonography between 11-14 weeks’ gestation has value in the detection of fetal aneuploidies. The frequency of hypoplastic NB varies between populations and is unknown in Mexico. Objective: To analyze the performance of hypoplastic NB for the early detection of fetal aneuploidies in a Mexican population. Material and methods: A nested case-control study in a cohort of Mexican pregnant women. The inclusion criteria were live fetus with crown-rump length (CRL) 45-84 mm and the result of perinatal karyotype or phenotype at birth. Ultrasonographic assessment of the NB was standardized. The statistical analyses were univariable, multiple logistic regression, Bayes’ theorem and performance. Results: A total of 65 cases and 1187 controls were studied, with maternal age of 17- 53 years. The frequency of hypoplastic NB was 1.6% (95% CI = 0.9-2.3) in euploid fetuses versus 44.6% (95% CI = 32.5-56.7) with aneuploidies (p < 0.001, χ2). Sensitivity for trisomy 21 was 58.3% (PPV 52.5%, NPV 98.7%). The probability of the hypoplastic NB was conditioned by aneuploidy (type), CRL, and nuchal translucency. The C-statistic of the Bayesian model was 0.904 (95% CI = 0.842-0.965). Conclusions: A Mexican model of the NB had added value in the early detection of fetal aneuploidies.
Keywords: Aneuploidy. Diagnostic imaging. Prenatal diagnosis. Maternal age. Nasal bone. Mexico. First trimester pregnancy.