title: Double occupancy.
authors.affiliation: Department of Obstetrics and Gynecology, Duke University Medical Center, Durham, NC, USA.
authors.forename: Haywood L
authors.initials: HL
authors.lastname: Brown
authors.forename: Brita K
authors.initials: BK
authors.lastname: Boyd
mesh_terms: D000328:Adult; D000650:Amnion / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D011247:Pregnancy; D014430:Twins, Monozygotic; D014463:Ultrasonography