Our results in a longitudinal study protocol at 5, 7, 8 and 10 weeks demonstrate that in normal pregnancies the arterial signals of the yolk sac circulation disappear and umbilicoplacental circulation simultaneously increases between 8 and 10 weeks. Spiral artery impedance decreases between 5 and 7 weeks. In the uterine and arcuate arteries a decrease in impedance and an increase in blood flow velocities occurs after 8 week. Vaginal bleeding with or without subchorionic hematoma is associated with an increased radial artery impedance at 7 weeks of pregnancy. Miscarriage could, however, not be predicted by means of Doppler ultrasonography. Significant improvement in the diastolic function of fetal heart between 6 and 7 weeks is accompanied by increased mean velocities across inflow and outflow tracts. Appearance of biphasic inflow pattern is associated with significant change in the systolic function of heart between 8 and 9 weeks. Atrioventricular valve recurgitation is a common finding at 10 week. These findings suggests that the first trimester of human pregnancy represents great transitional changes at all levels of fetal and placental hemodynamics.
|Original language||English (US)|
|Journal||Ultrasound in Medicine and Biology|
|Issue number||SUPPL. 2|
|Publication status||Published - 2000|
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging