Calcular Peso Feto Según Fémur
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Reviewed by Calculator Editorial Team
This calculator estimates fetal weight based on femur length using the Hadlock formula, which is commonly used in obstetrics. The calculation provides a quick reference for medical professionals and parents monitoring fetal growth.
How to Use This Calculator
To calculate fetal weight based on femur length:
- Enter the femur length in centimeters in the input field.
- Select the gestational age category (early, mid, or late).
- Click the "Calculate" button to get the estimated fetal weight.
- Review the result and interpretation provided.
The calculator uses the Hadlock formula, which is one of the most widely accepted methods for estimating fetal weight from ultrasound measurements.
Formula and Assumptions
The Hadlock formula for fetal weight estimation is:
Fetal Weight (grams) = (Femur Length (cm) × 100) × (1.285 - (0.003 × Gestational Age (weeks)))
Where:
- Femur Length is measured in centimeters
- Gestational Age is in weeks
This formula provides a reasonable estimate but should be used with caution as it may not account for all individual variations in fetal growth.
Note: The Hadlock formula is most accurate between 18 and 36 weeks of gestation. Results may be less reliable outside this range.
Interpreting Results
The estimated fetal weight provides a general indication of fetal growth. Here's how to interpret the results:
- For early gestation (18-22 weeks), weights below 500g may indicate potential growth issues.
- For mid-gestation (23-28 weeks), weights below 800g may warrant further evaluation.
- For late gestation (29-36 weeks), weights below 1200g may suggest growth concerns.
Always consult with a healthcare professional for a comprehensive evaluation of fetal growth.
Examples
Here are some example calculations using the Hadlock formula:
| Femur Length (cm) | Gestational Age (weeks) | Estimated Weight (grams) |
|---|---|---|
| 3.2 | 24 | 825.6 |
| 4.1 | 30 | 1,323.5 |
| 5.0 | 36 | 1,600.0 |
These examples demonstrate how the formula applies to different gestational stages and femur lengths.
Frequently Asked Questions
- What is the Hadlock formula?
- The Hadlock formula is an empirical equation used to estimate fetal weight based on femur length and gestational age. It's one of the most commonly used methods in obstetrics.
- When is this formula most accurate?
- The Hadlock formula is most reliable between 18 and 36 weeks of gestation. Results may be less accurate outside this range.
- Can this calculator replace professional medical advice?
- No, this calculator provides an estimate but should not replace professional medical evaluation. Always consult with a healthcare provider for accurate fetal growth assessment.
- What factors can affect fetal weight estimation?
- Several factors can influence fetal weight estimation, including maternal nutrition, genetic factors, and overall fetal health. The Hadlock formula accounts for some of these but not all.
- How often should I use this calculator?
- This calculator is most useful during routine prenatal check-ups or when monitoring fetal growth. Regular use can help track changes in fetal development.