Placental blood flow mapping in the first trimester of human pregnancy

Abstract

Human placental circulation in the first trimester of pregnancy remains a subject of scientific debate. Most of the acquired knowledge on the physiological background of maternal-fetal interface relies on old studies, most of them performed in non-hemochorial placentas and using light and electron microscopy for the pathological specimens' evaluation. Recently, some ultrasonographic research in this field, using pulsed-wave and/or colour Doppler, yielded contradictory results. The availability of these non-invasive methods should allow the in vivo investigation of placental circulation since early phases of human pregnancy. A more recent technique – Power Doppler – should be preferred considering its resolution, angle-independence, higher sensitivity for lower velocities and absence of known harmful bioeffects in the early periods of gestation. We provide an overview on first trimester maternal-fetal circulation, assessed by non-invasive techniques, namely by transvaginal power Doppler ultrasonography, tr...