First trimester sonographic diagnosis of orofacial defects. Review of literature.

Ultrasound has been used since the 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 and 20 weeks of gestational age, given that during the first trimester, a series of very frequent markers that determine a high risk of fetal anomalies can be evaluated. Among these markers, the most frequently studied are: increased nuchal translucency, the absence of nasal bones, increased tricuspid regurgitation, and 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 specificity for malformations such as oropalatine clefts, malformations of the nasal bones, and micrognathia. The purpose of this article is to make a comprehensive review of first trimester sonographic diagnosis of orofacial defects.