<font color="0000ff">Some info on Uterine Artery Notch:
What are the Uterine Arteries?
The uterine arteries provide blood to the uterus. Two arteries are present, one on the left and one on the right side of the uterus. Blood from the uterine arteries supplies blood to the muscles of the uterus and the placenta.
Type I. Abnormal Resistance Index
Once the waveforms are obtained and measured, the results are plotted on graphs to determine if blood flow during diastole is normal or abnormal. If the Resistance Index increases to a value above the upper range of normal, this identifies a fetus at risk or who may be undergrown (too small). To determine the Resistance Index the peak of systole (Sys Meas) is divided by the sum of the systolic (Sys Meas) and diastolic measurements (Dias Meas). A value greater than 0.58 is considered to be abnormal. One of the problems with this measurement is a higher false-positive rate than if one uses the presence or absence of notching (see below).
Type II. Mild Notching of the Uterine Artery
This is a more serious form than Type I because there is a "notch" at the beginning of diastole. The notch is the result of an increase in resistance to blood flowing into the placenta. The reason for this is because the blood vessels in the placenta are not enlarging or dilating as they should. When this occurs, notching is present in the Doppler waveform. However, as in this example, blood flow at the end of diastole appears to be normal, thus giving a normal Resistance Index. The presence of a notch, even with a normal Resistance Index, places the patient at high-risk for adverse fetal outcome.
Type III. Severe Notching with an Abnormal Resistance Index
When the Resistance Index is abnormal (low-diastolic flow) and a notch is present, this places the patient at the highest risk for adverse pregnancy outcome.
Benefits of Uterine Artery Surveillance
Recent studies have found that surveillance of high-risk fetuses with abnormal uterine blood flow may decrease morbidity and mortality. The majority of the earlier studies examined the uterine arteries during the second trimester of pregnancy (20-24 weeks) (Medical Literature). However, recent studies have suggested that identification of abnormal Doppler waveforms during the first-trimester and subsequent treatment with low-dose aspirin may be more beneficial than waiting until the second-trimeter to evaluate these vessels . The main problems with abnormal uterine artery blood flow that persists throughout the pregnancy is that there is an increased risk for pre-eclampsia (high blood pressure, protein in the urine) during the late second and third trimesters of pregnancy. When this occurs, the only treatment is delivery. In addition, fetuses of mothers who have an abnormal uterine artery Doppler waveform have an increased risk for abnormal fetal growth resulting in an undergrown, or small fetus with all of its consequences.
</font>