title: Research on the fetus using Doppler ultrasound in the first trimester: guiding ethical considerations.
authors.forename: F A
authors.initials: FA
authors.lastname: Chervenak
authors.forename: L B
authors.initials: LB
authors.lastname: McCullough
mesh_terms: D004992:Ethics, Medical; D005260:Female; D006801:Humans; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D012106:Research; D018608:Ultrasonography, Doppler; D016216:Ultrasonography, Prenatal