Estimated Fetal Weight(EFW) in Pregnancy – What is it, How to Calculate and Steps to Improve

According PubMed Central, during routine prenatal care, healthcare providers may perform ultrasound scans at different stages of pregnancy to monitor the growth and development of the fetus. These scans involve taking measurements of various fetal biometric parameters, such as head circumference, abdominal circumference, and femur length. These measurements are then used to calculate an estimated fetal weight.

The estimated fetal weight is determined using specific formulas that take into account the fetal biometric measurements, as well as the gestational age of the fetus. These formulas are derived from statistical data based on a large population of pregnancies.

The estimated fetal weight is used as a reference point to assess the growth of the fetus. It helps healthcare providers determine if the fetus is growing appropriately for its gestational age. Significant deviations from the expected weight range may indicate potential issues, such as fetal growth restriction (when the fetus is not growing adequately) or macrosomia (when the fetus is larger than average).

However, estimated fetal weight is just an estimation and may not be entirely accurate. Additionally, other factors, such as the mother’s health, medical history, and fetal well-being, are also considered in evaluating the overall health of the pregnancy.

Ultimately, the estimated fetal weight is used as one piece of information among several to assess the well-being of the fetus and guide medical decision-making during pregnancy. It’s always recommended to consult with a healthcare provider for personalized information and interpretation of EFW results specific to your pregnancy.

What is the Normal EFW in Pregnancy?

The normal estimated fetal weight (EFW) in pregnancy can vary depending on several factors, including gestational age, maternal factors, and population characteristics. It’s important to note that EFW is just an estimation and can have a margin of error. Additionally, every pregnancy is unique, and individual variations can occur.

Typically, the EFW is expressed as a percentile, which compares the estimated weight of the fetus to a reference population. For example, an EFW at the 50th percentile means that the estimated weight is right in the middle of the range for that gestational age. An EFW below the 10th percentile may be considered small for gestational age, while an EFW above the 90th percentile may be considered large for gestational age.

The specific ranges for normal EFW can vary slightly depending on the reference population and the specific gestational age. Generally, a normal EFW can range between the 10th and 90th percentiles. However, it’s important to consider individual factors, such as maternal height, weight, ethnicity, and medical history, as these factors can influence the expected weight range. Ultimately, the interpretation of EFW should be done by a healthcare provider.

How Do You Calculate EFW During Pregnancy?

The estimated fetal weight (EFW) during pregnancy is typically calculated using ultrasound measurements of specific fetal biometric parameters. The most common method used to calculate EFW is the Hadlock formula, which takes into account measurements of the biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), and femur length (FL).

Here is a general overview of how EFW is calculated using the Hadlock formula:

1. Biparietal Diameter(BPD)

This is the measurement of the fetal head from one parietal bone to the other. It is usually obtained by measuring the maximum distance between the two sides of the head. The BPD is typically measured in the axial plane of the fetal skull.

2. Head Circumference(HC)

This is the measurement around the widest part of the fetal head. It is obtained by measuring the circumference at the level of the BPD.

3. Abdominal Circumference(AC)

This is the measurement around the abdomen of the fetus. It is usually obtained by measuring the circumference at the level of the stomach and umbilical vein.

4. Femur Length (FL)

This is the measurement of the length of the fetal femur bone. It is typically obtained by visualizing and measuring the long bone in the fetal thigh.

Once these measurements (BPD, HC, AC, and FL) are obtained, the Hadlock formula is applied to calculate the estimated fetal weight (EFW). The formula takes into account the measurements and gestational age to estimate the weight.

It’s important to note that the accuracy of the EFW calculation can depend on various factors, including the quality of the ultrasound images and the experience of the sonographer performing the measurements. Additionally, the formula used and the reference population can vary, which can affect the EFW calculation. It’s always best to consult with a healthcare provider who can perform the ultrasound examination and interpret the EFW results based on your specific pregnancy and medical history.

Should You Be Worried If EFW is Less Than Normal?

If the estimated fetal weight (EFW) is less than the expected range or below the 10th percentile, it may be an indication of potential fetal growth restriction (FGR) or small-for-gestational-age (SGA) fetus. In such cases, it is reasonable to have some level of concern, but it’s important to remember that EFW is just one piece of information and should be interpreted in the context of the overall pregnancy.

Various factors can contribute to a lower-than-normal EFW, including maternal factors (such as smoking, poor nutrition, or certain medical conditions), placental issues, genetic factors, and fetal factors. It’s essential to work closely with your healthcare provider to investigate further and assess the underlying cause.

If your healthcare provider is concerned about a lower EFW, they may recommend additional tests or monitoring to evaluate the well-being of the fetus. These tests may include Doppler ultrasound to assess blood flow in the umbilical artery, non-stress tests to monitor fetal heart rate patterns, or biophysical profile tests to evaluate various fetal well-being parameters.

Your healthcare provider will consider these test results along with your medical history, fetal movement patterns, and other relevant factors to make decisions about the management of your pregnancy. This may include more frequent monitoring, close observation, and potentially an early delivery if warranted.

[Read : Slow Fetal Growth During Pregnancy]

Step You Can Take to Improve EFW in Pregnancy

During pregnancy, there are several steps you can take to support healthy fetal growth and potentially improve the estimated fetal weight (EFW):

1. Balanced and Nutritious Diet

Consume a well-balanced diet that includes a variety of fruits, vegetables, whole grains, lean proteins, and healthy fats. Adequate nutrition is essential for proper fetal growth and development of the fetus.

2. Sufficient Weight Gain

Aim to achieve appropriate weight gain during pregnancy, as recommended by your healthcare provider. Weight gain within the recommended range can contribute to healthy fetal growth. However, it’s important to gain weight gradually and healthily as excessive weight gain can pose risks.

3. Prenatal Vitamins and Supplements

Take prenatal vitamins and supplements as recommended by your healthcare provider. These can help ensure you’re receiving essential nutrients, such as folic acid, iron, and calcium, which are crucial for fetal development.

[Read : How To Choose Prenatal Vitamins During Pregnancy]

4. Regular Prenatal Care

Attend all scheduled prenatal appointments and follow your healthcare provider’s recommendations for check-ups, screenings, and ultrasounds. Regular prenatal care allows your healthcare provider to monitor the growth and development of the fetus and address any concerns promptly.

5. Avoid Harmful Substances

Eliminate or reduce the consumption of substances that can be harmful to fetal growth, such as alcohol, tobacco, and illicit drugs. These substances can negatively impact fetal development and growth.

6. Manage Your Health Conditions

Maintain close communication with your doctor to manage and control any underlying health conditions you may have, such as diabetes or hypertension, throughout your pregnancy. Proper management of underlying health conditions can help optimize fetal growth.

7. Monitor Fetal Movement

Pay attention to the fetal movement patterns and report any significant changes or decreases in movement to your healthcare provider. Regular fetal movement is a positive sign of fetal well-being.

It’s important to note that while these measures can support healthy fetal growth, they may not guarantee a specific EFW outcome. Each pregnancy is unique, and various factors can influence fetal growth. Always consult with your healthcare provider for personalized guidance and recommendations based on your specific circumstances.

EFW is one of the tests which determines fetal health during pregnancy. It estimates the fetal weight which helps in analyzing the growth and development of the fetus.

FAQ’s

1. What is EFW Full Form in Pregnancy?

In pregnancy, EFW stands for Estimated fetal weight.

Read Also: How To Increase Fetal Weight During Pregnancy?