title: Routine ultrasound has not been shown to be more accurate than the calendar method.
authors.forename: R
authors.initials: R
authors.lastname: Zimmermann
authors.forename: J
authors.initials: J
authors.lastname: Wisser
mesh_terms: D005260:Female; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D013997:Time Factors; D016216:Ultrasonography, Prenatal / Q000592:standards*