ultrasound, prenatal, sonography, ultrasonography, obstetrical ultrasound, ultrasound scans,  obstetric ultrasound, antenatal, ultrasound in obstetrics, doppler, doppler ultrasound, ultrasound in pregnancy, pregnancy, medical, health, joseph WooThe umbilical artey blood flow systolic to end-diastolic ratio is used as a measure of fetal compromise.
The ratio decreases towards term, from about 3.5 at 24 weeks to about 2.2 at term.
As the diastolic flow becomes diminished in fetal compromise, the systolic/diastolic ratio will rise.



ultrasound, prenatal, sonography, antenatal, ultrasonography, obstetrical ultrasound, ultrasound scans,  antenatal, obstetric ultrasound, ultrasound in obstetrics, doppler, doppler ultrasound, ultrasound in pregnancy, pregnancy, medical, health, joseph WooThe UA ratio at 24 weeks in a fetus with severe intrauterine growth retardation. A represented the systolic value and B the end-diastolic value. The ratio was 4.6.


ultrasound, prenatal, sonography, ultrasonography, obstetrical ultrasound, ultrasound scans,  obstetric ultrasound, ultrasound in obstetrics, doppler, doppler ultrasound, ultrasound in pregnancy, pregnancy, medical, health, joseph WooThe UA ratio at 28 weeks. The ratio had increased to 5.4.


ultrasound, prenatal, sonography, ultrasonography, obstetrical ultrasound, ultrasound scans,  obstetric ultrasound, ultrasound in obstetrics, doppler, doppler ultrasound, ultrasound in pregnancy, pregnancy, medical, health, joseph WooThe UA ratio at 32 weeks. The ratio had increased to infinity because of an absence of end-diastolic flow. The fetus is at tremendous risk of intrauterine death.