Placenta · 1988 · 14 citations · 0 references
MedicineMaternal HealthObstetricsObstetric UltrasoundUltrasonographyUltrasoundEarly Pregnancy AssessmentFirst-trimester UltrasoundObstetric UltrasonographySecond Trimester UltrasoundThird Trimester UltrasoundTransvaginal UltrasoundIntrapartum Ultrasound AssessmentObstetric ExaminationPregnancy Ultrasonography