Ultrasonic imaging of the amniotic and chorionic cavities.
This paper presents two cases illustrating separate chorionic and amniotic sacs at 5 to 6 weeks of estimated gestational age. With higher resolution scanning units and higher-frequency transducers, the delineation of the amniotic membrane can be seen before it fuses with the chorionic membrane; this should not be interpretated as an abnormality.
D000328:Adult; D000650:Amnion; D002823:Chorion; D005260:Female; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D014463:Ultrasonography