The Middle Cerebral Artery (MCA) Doppler ultrasound is a critical non-invasive diagnostic method used in modern obstetrics and perinatology. The MCA calculator on this page helps you interpret Doppler ultrasound results by calculating the Multiple of the Median (MoM) for a given gestational age and MCA peak systolic velocity (PSV). This calculation supports the detection and monitoring of fetal anemia in both singleton and twin pregnancies.
MCA Doppler Calculator
What Is the MCA Doppler?
The MCA, or middle cerebral artery, is one of the major blood vessels supplying the brain. During pregnancy, the fetal MCA can be assessed using Doppler ultrasound to determine blood flow velocity. An abnormal increase in MCA velocity can indicate fetal anemia, particularly in pregnancies affected by Rh isoimmunization, parvovirus B19 infection, or twin-to-twin transfusion syndrome.
MCA Doppler is a vital component of non-invasive fetal surveillance. It is often used in conjunction with other Doppler indices and clinical data to form a complete assessment of fetal well-being.
Why Use an MCA Calculator?
The MCA Doppler calculator online simplifies the process of interpreting Doppler ultrasound values by providing:
- Expected median MCA peak systolic velocity (PSV) for the selected gestational age
- MoM value (Multiple of Median), which helps assess the severity of fetal anemia
- A clear interpretation of whether the MCA velocity is within normal range or suggestive of anemia
This tool is especially helpful in routine prenatal care and high-risk pregnancy monitoring. It serves as a decision-support resource, not a replacement for clinical judgment.
Clinical Use of MCA Doppler in Perinatology
The MCA Doppler is often used in the following clinical situations:
- Suspected fetal anemia
- Rh alloimmunization
- Parvovirus B19 infection
- Intrauterine growth restriction (IUGR)
- Preeclampsia risk assessment
- Monochorionic twin pregnancy complications
In all of these cases, an elevated MCA peak systolic velocity (PSV) typically correlates with anemia due to reduced blood viscosity and increased cardiac output.
By using a gestational age-specific median, the MoM value offers a standardized, comparable measure for evaluating Doppler results.
How Is the MoM for MCA Calculated?
To calculate the MCA MoM, you need two values:
- Gestational age in weeks
- Observed MCA PSV (measured in cm/s via Doppler ultrasound)
The calculator compares the observed MCA PSV to the expected median value at that gestational age. The formula is:
MoM = Observed MCA PSV / Expected Median MCA PSV
A MoM ≥ 1.5 is often considered a threshold indicating moderate to severe fetal anemia, prompting further evaluation or intervention.
Benefits of Using a Web-Based MCA Calculator
- Accuracy: Based on published reference data and research formulas
- Speed: Instant MoM calculations without manual lookup
- Clinical relevance: Interprets results based on standard medical guidelines
- Accessibility: Can be used on any device, during or after a consultation
Our MCA Doppler velocity chart and reference ranges are based on validated studies, such as those by Mari et al., which continue to shape clinical best practices.
Limitations and Clinical Disclaimer
This MCA calculator is a supportive tool designed for use by medical professionals. While it can assist in screening for fetal anemia, it does not replace clinical judgment or direct patient assessment. For patients with abnormal results, referral to maternal-fetal medicine and further diagnostic evaluation is strongly advised.
Final Thoughts
The MCA Doppler ultrasound is a cornerstone of non-invasive fetal surveillance, and the MCA calculator makes interpretation faster, clearer, and more standardized. Whether managing high-risk pregnancies or routine monitoring, this tool helps guide clinical decision-making in a reliable, evidence-based manner.
Use the calculator above by entering the gestational age and MCA peak systolic velocity, and get the MoM value instantly. Accurate, fast, and professional — designed to support quality prenatal care.
How is MCA calculated?
MCA refers to the Middle Cerebral Artery peak systolic velocity (PSV), measured in cm/s during a Doppler ultrasound. It’s used to assess fetal blood flow and detect anemia.
How to calculate MCA?
MCA PSV is measured directly via ultrasound. To interpret the result, compare it to the gestational age-specific median value and calculate the MoM (Multiple of Median):
MoM = Observed MCA PSV / Median MCA PSV.
How to calculate MCA percentage?
To get the MCA percentage relative to normal:
(Observed MCA PSV / Median MCA PSV) × 100.
A result over 150% may suggest fetal anemia.
How to calculate MCA score?
MCA “score” typically refers to the MoM value. There’s no standardized “score,” but a MoM ≥ 1.5 is often considered a threshold for moderate to severe fetal anemia.