Ultrasonographic findings in the first trimester of pregnancy and utility of the retronasal triangle for the diagnosis of orofacial defects

Abstract

Ultrasound has been used since 1950s as a useful tool for the screening of several pregnancy abnormalities. The National Institute for Excellence in Health and Care (NICE) guidelines for prenatal control recommend its routine use between 12 to 20 weeks of gestational age, given that during the first trimester, a serie of very frequent markers that determine a high risk of fetal anomalies can be evaluated. Among these markers, the most frequently studied are: the increased nuchal translucency, the absence of nasal bones, the increased tricuspid regurgitation, and the altered flow in the venous duct. There is also a new ultrasound technique, consisting of the evaluation of the retronasal triangle view, which captures the coronal plane of the face in which the primary palate and the frontal process of the maxillary are simultaneously visualized, presenting high sensitivity and especificity for malformations such as oropalatine clefts, malformations of the nasal bones and micrognathia.