Chama, C M From low-lying implantation to placenta praevia: a longitudinal ultrasonic assessment. [electronic resource] - Journal of obstetrics and gynaecology : the journal of the Institute of Obstetrics and Gynaecology Aug 2004 - 516-8 p. digital Publication Type: Journal Article ISSN: 0144-3615 Standard No.: 10.1080/01443610410001722545 doi Subjects--Topical Terms: AdultFemaleHumansIncidenceLongitudinal StudiesNigeria--epidemiologyPlacenta Previa--diagnostic imagingPregnancyPregnancy OutcomePregnancy Trimester, FirstProspective StudiesUltrasonography, Prenatal