title: In search for the 'third point'.
authors.forename: D A
authors.initials: DA
authors.lastname: Pedreira
mesh_terms: D005260:Female; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D012723:Sex; D012732:Sex Determination Analysis; D012733:Sex Differentiation; D016216:Ultrasonography, Prenatal