title: The lambda sign in twin pregnancies.
authors.forename: W
authors.initials: W
authors.lastname: Sepulveda
authors.forename: N J
authors.initials: NJ
authors.lastname: Sebire
authors.forename: K H
authors.initials: KH
authors.lastname: Nicolaides
mesh_terms: D002823:Chorion / Q000000981:diagnostic imaging*; D005260:Female; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D011272:Pregnancy, Multiple; D014427:Twins; D016216:Ultrasonography, Prenatal