When are Doppler (Doppler ultrasound) studies typically conducted during antepartum care?

From the Guidelines

Doppler ultrasound studies are typically conducted during antepartum care starting at the first diagnosis of preeclampsia or fetal growth restriction, with follow-up studies performed at regular intervals depending on clinical indications, as recommended by the most recent guidelines 1.

Key Considerations

• For high-risk pregnancies, such as those complicated by fetal growth restriction or preeclampsia, Doppler studies are performed more frequently, often every 2-4 weeks or even weekly in severe cases, to assess placental function and fetal well-being 1.
• The timing and frequency of Doppler studies should be individualized based on the specific clinical scenario, with more frequent monitoring as term approaches or if abnormalities are detected 1.
• Doppler ultrasound provides valuable information about placental perfusion and fetal hemodynamics, helping clinicians identify compromised fetuses who may benefit from closer monitoring or earlier delivery 1.

Specific Recommendations

• In confirmed preeclampsia or fetal growth restriction, serial evaluation of fetal growth, amniotic fluid volume, and UA Doppler are recommended from 24-26 weeks’ gestation until birth, with fetal growth evaluated no more frequently than at 2 weekly intervals 1.
• If the UA Doppler demonstrates increased resistance or absent end-diastolic flow, the sonographic surveillance should be increased to weekly intervals or more frequently if deemed necessary by the managing clinician 1.
• The most recent guidelines recommend against routine Doppler studies of other vessels in cases of fetal growth restriction, particularly if the umbilical artery evaluation is normal 1.

Clinical Implications

• Doppler ultrasound studies are a crucial tool in assessing fetal well-being and guiding clinical management in high-risk pregnancies 1.
• The results of Doppler studies should be interpreted in the context of the individual clinical scenario, taking into account factors such as gestational age, fetal growth restriction, and maternal medical conditions 1.
• Clinicians should be aware of the potential limitations and pitfalls of Doppler ultrasound studies, including the risk of false positives and false negatives, and use their clinical judgment to guide decision-making 1.

From the Research

Doppler Studies During Antepartum Care

Doppler ultrasound studies are typically conducted during antepartum care to assess fetal well-being, particularly in high-risk pregnancies. The timing of these studies can vary depending on the specific risk factors and the gestational age of the fetus.

• Doppler studies can be performed as early as 19-22 weeks of gestation in high-risk pregnancies 2.
• In some cases, Doppler studies may be conducted monthly if the pregnancy is considered high-risk, or once at 32 weeks if considered low-risk 2.
• For high-risk pregnancies, such as those with preeclampsia or fetal growth restriction, Doppler studies may be performed more frequently, such as every 1-2 weeks, to monitor fetal well-being 3, 4, 5.
• The American College of Obstetricians and Gynecologists (ACOG) recommends that Doppler ultrasound studies be performed in high-risk pregnancies, but does not specify a particular gestational age for these studies.

Indications for Doppler Studies

Doppler studies are typically indicated in the following situations:

• High-risk pregnancies, such as those with preeclampsia or fetal growth restriction 3, 4, 5.
• Pregnancies with a history of fetal growth restriction or stillbirth 4.
• Pregnancies with abnormal fetal heart rate tracings or other signs of fetal distress 5.
• Pregnancies with multiple gestations or other complications 6, 2.

Parameters Assessed by Doppler Studies

Doppler studies can assess various parameters, including:

• Umbilical artery Doppler velocimetry, which measures blood flow in the umbilical artery 3, 4, 5, 6.
• Middle cerebral artery Doppler velocimetry, which measures blood flow in the middle cerebral artery 3, 4, 5.
• Uterine artery Doppler velocimetry, which measures blood flow in the uterine artery 3, 2.
• Cerebroplacental ratio, which measures the ratio of blood flow in the middle cerebral artery to the umbilical artery 3.