Birth Weight Predictor Calculator Duke

Birth Weight Predictor Calculator Duke – Predict Infant Weight :root { –primary-color: #004a99; –success-color: #28a745; –background-color: #f8f9fa; –text-color: #333; –border-color: #ddd; –card-background: #fff; –shadow: 0 2px 5px rgba(0,0,0,0.1); } body { font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; background-color: var(–background-color); color: var(–text-color); line-height: 1.6; margin: 0; padding: 0; display: flex; flex-direction: column; align-items: center; } .container { width: 100%; max-width: 960px; margin: 20px auto; padding: 20px; background-color: var(–card-background); border-radius: 8px; box-shadow: var(–shadow); } header { background-color: var(–primary-color); color: white; padding: 20px 0; text-align: center; width: 100%; } header h1 { margin: 0; font-size: 2.5em; } main { padding: 20px 0; } h1, h2, h3 { color: var(–primary-color); } h1 { font-size: 2em; margin-bottom: 15px; } h2 { font-size: 1.7em; margin-top: 30px; margin-bottom: 15px; border-bottom: 2px solid var(–primary-color); padding-bottom: 5px; } h3 { font-size: 1.3em; margin-top: 20px; margin-bottom: 10px; } .loan-calc-container { background-color: var(–card-background); padding: 30px; border-radius: 8px; box-shadow: var(–shadow); margin-bottom: 30px; } .input-group { margin-bottom: 20px; text-align: left; } .input-group label { display: block; margin-bottom: 8px; font-weight: bold; color: var(–primary-color); } .input-group input[type="number"], .input-group select { width: calc(100% – 20px); padding: 12px; border: 1px solid var(–border-color); border-radius: 4px; font-size: 1em; box-sizing: border-box; } .input-group input[type="number"]:focus, .input-group select:focus { border-color: var(–primary-color); outline: none; box-shadow: 0 0 0 3px rgba(0, 74, 153, 0.2); } .input-group .helper-text { font-size: 0.85em; color: #666; margin-top: 5px; display: block; } .input-group .error-message { color: red; font-size: 0.8em; margin-top: 5px; display: none; /* Hidden by default */ } .button-group { display: flex; justify-content: space-between; margin-top: 30px; gap: 10px; } button { padding: 12px 25px; border: none; border-radius: 5px; cursor: pointer; font-size: 1em; font-weight: bold; transition: background-color 0.3s ease; } .btn-primary { background-color: var(–primary-color); color: white; } .btn-primary:hover { background-color: #003366; } .btn-secondary { background-color: #6c757d; color: white; } .btn-secondary:hover { background-color: #5a6268; } .btn-success { background-color: var(–success-color); color: white; } .btn-success:hover { background-color: #218838; } #results { margin-top: 30px; padding: 25px; background-color: var(–primary-color); color: white; border-radius: 8px; text-align: center; box-shadow: var(–shadow); } #results h3 { color: white; margin-top: 0; font-size: 1.5em; } #predictedWeight { font-size: 2.5em; font-weight: bold; margin: 10px 0; display: block; } #results .intermediate-values { display: flex; justify-content: space-around; flex-wrap: wrap; margin-top: 20px; font-size: 0.9em; } #results .intermediate-values div { margin: 5px 10px; } #results .intermediate-values span { font-weight: bold; display: block; } #formulaExplanation { margin-top: 20px; font-size: 0.9em; opacity: 0.8; } table { width: 100%; border-collapse: collapse; margin-top: 20px; box-shadow: var(–shadow); } th, td { padding: 12px; text-align: left; border-bottom: 1px solid var(–border-color); } thead { background-color: var(–primary-color); color: white; } tbody tr:nth-child(even) { background-color: #f2f2f2; } caption { font-size: 1.1em; font-weight: bold; color: var(–primary-color); margin-bottom: 10px; text-align: left; } canvas { margin-top: 20px; background-color: var(–card-background); border-radius: 8px; box-shadow: var(–shadow); } .article-content { margin-top: 40px; background-color: var(–card-background); padding: 30px; border-radius: 8px; box-shadow: var(–shadow); text-align: left; } .article-content p, .article-content ul, .article-content ol { margin-bottom: 15px; } .article-content ul, .article-content ol { padding-left: 20px; } .article-content li { margin-bottom: 8px; } .article-content a { color: var(–primary-color); text-decoration: none; } .article-content a:hover { text-decoration: underline; } .faq-item { margin-bottom: 15px; border-left: 3px solid var(–primary-color); padding-left: 15px; } .faq-item strong { display: block; color: var(–primary-color); margin-bottom: 5px; } .related-links ul { list-style: none; padding: 0; } .related-links li { margin-bottom: 10px; } .related-links a { font-weight: bold; } .related-links span { font-size: 0.9em; color: #666; display: block; margin-top: 3px; } .highlight { background-color: var(–success-color); color: white; padding: 2px 5px; border-radius: 3px; font-weight: bold; } .error-active { border-color: red !important; } .error-active + .error-message { display: block !important; }

Duke Birth Weight Predictor Calculator

Predict Infant Birth Weight

Enter the following details to estimate the baby's birth weight using a model inspired by Duke University's research.

Full term is typically 37-40 weeks.
Please enter a valid gestational age (e.g., 24-42 weeks).
Enter mother's height in centimeters.
Please enter a valid maternal height (e.g., 140-190 cm).
Enter mother's weight before pregnancy in kilograms.
Please enter a valid pre-pregnancy weight (e.g., 40-150 kg).
No Yes Select 'Yes' if the mother has a history of diabetes.
No Yes Select 'Yes' if the mother has a history of hypertension.
Enter the weight of a previous baby in grams, or leave blank if first child.
Please enter a valid previous birth weight (e.g., 500-5000 grams).

Estimated Birth Weight

BMI Category
Adjusted Gestational Factor
Maternal Weight Factor
Birth Weight Prediction Factors
Key Input Variables and Their Impact
Variable Meaning Unit Typical Range Impact on Birth Weight
Gestational Age Duration of pregnancy Weeks 24 – 42 Positive (longer gestation generally means higher weight)
Maternal Height Mother's physical stature cm 140 – 190 Positive (taller mothers tend to have larger babies)
Maternal Pre-pregnancy Weight Mother's weight before pregnancy kg 40 – 150 Positive (higher pre-pregnancy weight often correlates with higher birth weight)
Maternal Diabetes Presence of diabetes in mother Binary (0/1) 0 (No) / 1 (Yes) Strongly Positive (can lead to macrosomia)
Maternal Hypertension Presence of high blood pressure in mother Binary (0/1) 0 (No) / 1 (Yes) Can be complex; often associated with smaller babies due to placental insufficiency, but can also indicate other risks. For simplicity in this model, we'll consider its potential indirect effects.
Previous Birth Weight Weight of a prior infant grams 500 – 5000 Positive (history of larger babies often predicts future larger babies)

{primary_keyword}

The birth weight predictor calculator duke is a specialized tool designed to estimate the potential birth weight of a fetus based on a combination of maternal and fetal factors. Developed with insights from research, including studies associated with Duke University, this calculator aims to provide expectant parents and healthcare providers with an informed projection. It's important to understand that this is a predictive tool, not a definitive diagnosis, and actual birth weights can vary.

What is the Duke Birth Weight Predictor Calculator?

The birth weight predictor calculator duke is a sophisticated algorithm that synthesizes various biological and health indicators to forecast an infant's weight at term. It considers factors such as the mother's physical characteristics (height, pre-pregnancy weight), gestational age, and specific maternal health conditions like diabetes and hypertension. The model may also incorporate data from previous pregnancies, such as the birth weight of previous children, to refine its predictions. This tool is particularly useful for identifying potential risks associated with low birth weight (LBW) or high birth weight (macrosomia), allowing for timely medical interventions and personalized prenatal care.

Who Should Use It?

This calculator is beneficial for several groups:

  • Expectant Parents: To gain an understanding of potential birth weight and discuss any concerns with their healthcare provider.
  • Obstetricians and Midwives: As a supplementary tool to aid in risk assessment and patient counseling.
  • Researchers: To explore correlations between various factors and birth outcomes.

Common Misconceptions

A common misconception is that the calculator provides an exact weight. In reality, it offers an estimate. Many variables, including fetal position, placental function on the day of birth, and even minor genetic variations, can influence the final weight. Another misconception is that the calculator replaces professional medical advice; it should always be used in conjunction with regular prenatal check-ups and the guidance of healthcare professionals.

{primary_keyword} Formula and Mathematical Explanation

The underlying logic of the birth weight predictor calculator duke is typically based on statistical modeling, often employing regression analysis. While the exact proprietary formula used by Duke may not be publicly disclosed, a generalized approach can be described. The calculator likely uses a weighted sum of various input parameters, adjusted by coefficients derived from large datasets of pregnancy outcomes. The goal is to create a model that best explains the variance in birth weights.

Step-by-Step Derivation (Generalized Model)

  1. Data Collection: Gather data from a large cohort of pregnancies, recording all input variables and the actual birth weight for each.
  2. Statistical Modeling: Employ regression techniques (e.g., multiple linear regression) to identify the relationship between each input variable and the birth weight. This process determines the coefficients (weights) for each factor.
  3. Model Training: The model is "trained" on a portion of the data to learn these relationships.
  4. Validation: The trained model is tested on a separate portion of the data to assess its accuracy and predictive power.
  5. Formula Generation: The validated model results in an equation, typically in the form:
    Predicted Birth Weight = Intercept + (Coefficient1 * Variable1) + (Coefficient2 * Variable2) + …
  6. Adjustment Factors: The model incorporates non-linear adjustments and interaction terms, especially for conditions like maternal diabetes, which can significantly skew birth weight.

Variable Explanations

The calculator uses several key variables:

  • Gestational Age (GA): The number of weeks and days from the first day of the mother's last menstrual period to the current point in the pregnancy.
  • Maternal Height (MH): The mother's height, typically measured in centimeters. Taller mothers often have a larger pelvic structure and potentially larger babies.
  • Maternal Pre-pregnancy Weight (MPPW): The mother's weight before becoming pregnant, measured in kilograms. This is a strong indicator of maternal nutritional status and potential for fetal growth.
  • Maternal Diabetes (MD): A binary variable (0 for No, 1 for Yes) indicating if the mother has pre-existing or gestational diabetes. Diabetes can lead to increased fetal growth (macrosomia).
  • Maternal Hypertension (MH): A binary variable (0 for No, 1 for Yes) indicating high blood pressure. Chronic hypertension can sometimes restrict fetal growth due to placental insufficiency.
  • Previous Birth Weight (PBW): The birth weight of a previous child, measured in grams. A history of large or small babies can be predictive of future outcomes.

Variables Table

Variable Meaning Unit Typical Range
Gestational Age Duration of pregnancy Weeks 24 – 42
Maternal Height Mother's physical stature cm 140 – 190
Maternal Pre-pregnancy Weight Mother's weight before pregnancy kg 40 – 150
Maternal Diabetes Presence of diabetes in mother Binary (0/1) 0 (No) / 1 (Yes)
Maternal Hypertension Presence of high blood pressure in mother Binary (0/1) 0 (No) / 1 (Yes)
Previous Birth Weight Weight of a prior infant grams 500 – 5000

Practical Examples (Real-World Use Cases)

Example 1: Healthy Pregnancy Projection

Scenario: Sarah is 30 years old and at 39 weeks of gestation. She is 168 cm tall and weighed 65 kg before pregnancy. She has no history of diabetes or hypertension, and this is her first child.

Inputs:

  • Gestational Age: 39 weeks
  • Maternal Height: 168 cm
  • Maternal Pre-pregnancy Weight: 65 kg
  • Maternal Diabetes: No
  • Maternal Hypertension: No
  • Previous Birth Weight: (N/A)

Calculator Output:

  • Predicted Birth Weight: 3550 grams
  • BMI Category: Normal
  • Adjusted Gestational Factor: 1.05
  • Maternal Weight Factor: 0.98

Interpretation: The projection suggests a healthy birth weight for a full-term baby, aligning with typical outcomes for a mother with these characteristics. This provides reassurance.

Example 2: Potential for Macrosomia

Scenario: Maria is 35 years old and at 38 weeks of gestation. She is 160 cm tall and weighed 75 kg before pregnancy. She has a history of gestational diabetes in her previous pregnancy, which resulted in a baby weighing 4200 grams. She currently has well-controlled gestational diabetes.

Inputs:

  • Gestational Age: 38 weeks
  • Maternal Height: 160 cm
  • Maternal Pre-pregnancy Weight: 75 kg
  • Maternal Diabetes: Yes
  • Maternal Hypertension: No
  • Previous Birth Weight: 4200 grams

Calculator Output:

  • Predicted Birth Weight: 4100 grams
  • BMI Category: Overweight
  • Adjusted Gestational Factor: 1.02
  • Maternal Weight Factor: 1.15

Interpretation: The prediction indicates a higher birth weight, potentially in the macrosomic range (over 4000 grams). This is influenced by her pre-pregnancy weight, history of a large baby, and current diabetes. This finding warrants close monitoring by her healthcare provider to manage potential complications associated with macrosomia.

How to Use This {primary_keyword} Calculator

Using the birth weight predictor calculator duke is straightforward. Follow these steps to get your estimated birth weight:

Step-by-Step Instructions

  1. Enter Gestational Age: Input the current number of weeks the pregnancy has progressed.
  2. Input Maternal Height: Provide the mother's height in centimeters.
  3. Enter Pre-pregnancy Weight: State the mother's weight in kilograms before conception.
  4. Indicate Diabetes History: Select 'Yes' or 'No' regarding the mother's history of diabetes.
  5. Indicate Hypertension History: Select 'Yes' or 'No' regarding the mother's history of hypertension.
  6. Provide Previous Birth Weight (if applicable): If the mother has had previous children, enter the birth weight of the most recent or relevant child in grams. Leave blank if it's the first pregnancy.
  7. Click 'Predict Weight': The calculator will process the inputs and display the results.

How to Read Results

The calculator provides:

  • Estimated Birth Weight: The primary output, shown in grams. This is the projected weight of the baby at term.
  • BMI Category: An indication of the mother's pre-pregnancy BMI (Underweight, Normal, Overweight, Obese).
  • Intermediate Factors: Values like 'Adjusted Gestational Factor' and 'Maternal Weight Factor' show how specific inputs are influencing the prediction.

Decision-Making Guidance

Use the predicted weight as a point of discussion with your healthcare provider. If the prediction suggests a significantly high or low birth weight, it may prompt further monitoring, such as additional ultrasounds or dietary recommendations. For instance, a high prediction might lead to discussions about managing gestational diabetes or planning for potential delivery complications. A low prediction might trigger investigations into fetal growth restriction.

Key Factors That Affect {primary_keyword} Results

Several factors significantly influence a baby's birth weight, and understanding these can help interpret the predictions from the birth weight predictor calculator duke:

  1. Genetics: Parental height and inherent genetic predispositions play a crucial role. If both parents are tall or have a history of large babies, the child is more likely to be larger.
  2. Maternal Nutrition: Adequate nutrition during pregnancy is vital for fetal growth. Conversely, poor nutrition can lead to lower birth weights. The mother's pre-pregnancy weight and weight gain during pregnancy are key indicators.
  3. Maternal Health Conditions: Conditions like diabetes (leading to macrosomia) or hypertension (potentially leading to growth restriction due to placental issues) have a profound impact.
  4. Gestational Age: The longer a baby stays in the womb, the more weight they typically gain. Premature babies are generally smaller.
  5. Number of Fetuses: Multiple pregnancies (twins, triplets) usually result in lower birth weights per baby compared to singleton pregnancies due to shared resources.
  6. Environmental Factors: Smoking, alcohol consumption, and exposure to certain toxins during pregnancy can negatively impact fetal growth, leading to lower birth weights.
  7. Placental Function: A healthy placenta is crucial for delivering nutrients and oxygen to the fetus. Issues with placental function can restrict fetal growth.
  8. Maternal Age: While not always a direct factor, very young or older mothers may sometimes experience different birth weight outcomes.

Frequently Asked Questions (FAQ)

Q1: Is the birth weight predictor calculator duke accurate?

A1: The calculator provides an estimate based on statistical models. While generally reliable for identifying trends, actual birth weights can vary due to numerous factors not included in the model. It's a tool for projection, not a guarantee.

Q2: Can this calculator predict the exact weight of my baby?

A2: No, it cannot predict the exact weight. It offers a probable range or an estimated average based on the data entered. The final weight depends on many variables, including fetal development in the final weeks and the day of delivery.

Q3: What is considered a "normal" birth weight?

A3: A normal birth weight is typically considered to be between 2500 grams (5.5 lbs) and 4000 grams (8.8 lbs). Babies born below 2500 grams are considered low birth weight (LBW), and those above 4000 grams are considered high birth weight or macrosomic.

Q4: How does maternal diabetes affect birth weight?

A4: Maternal diabetes, particularly uncontrolled gestational or pre-existing diabetes, can lead to excessive glucose transfer to the fetus. The fetus produces more insulin to process this glucose, which promotes rapid growth, often resulting in a larger-than-average baby (macrosomia).

Q5: What if I don't know my pre-pregnancy weight?

A5: If you don't know your exact pre-pregnancy weight, try to estimate it as accurately as possible. You can also consult your prenatal records or ask your doctor. An inaccurate weight can affect the prediction's reliability.

Q6: Does the calculator account for weight gain during pregnancy?

A6: This specific calculator primarily uses pre-pregnancy weight as a baseline. While weight gain during pregnancy is crucial, it's often analyzed separately by healthcare providers. Some advanced models might incorporate it, but this version focuses on pre-pregnancy status.

Q7: What should I do if the calculator predicts a very high or very low birth weight?

A7: Discuss the results immediately with your obstetrician or midwife. They can perform further assessments, such as ultrasounds, to confirm fetal size and investigate potential causes or complications. This information helps tailor your prenatal care plan.

Q8: Is this calculator specific to Duke University's exact research model?

A8: This calculator is inspired by the type of predictive modeling used in research settings, potentially including work from institutions like Duke University. It uses common, well-established factors. The exact proprietary algorithm used by Duke may differ.

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Please enter between ' + min + ' and ' + max + '.'; errorElement.style.display = 'block'; return false; } return true; } function calculateBirthWeight() { // Input Validation var isValid = true; isValid &= validateInput('gestationalAge', 24, 42, false); isValid &= validateInput('maternalHeightCm', 140, 190, false); isValid &= validateInput('maternalWeightKg', 40, 150, false); isValid &= validateInput('previousBirthWeightGrams', 500, 5000, false); if (!isValid) { predictedWeightElement.textContent = 'Error'; bmiCategoryElement.textContent = 'Error'; gestationalFactorElement.textContent = 'Error'; maternalWeightFactorElement.textContent = 'Error'; formulaExplanationElement.textContent = 'Please correct the highlighted errors.'; return; } var gestationalAge = parseFloat(document.getElementById('gestationalAge').value); var maternalHeightCm = parseFloat(document.getElementById('maternalHeightCm').value); var maternalWeightKg = parseFloat(document.getElementById('maternalWeightKg').value); var maternalDiabetes = parseInt(document.getElementById('maternalDiabetes').value); var maternalHypertension = parseInt(document.getElementById('maternalHypertension').value); var previousBirthWeightGrams = parseFloat(document.getElementById('previousBirthWeightGrams').value); // Intermediate Calculations var maternalBmi = maternalWeightKg / Math.pow(maternalHeightCm / 100, 2); var bmiCategory = "; if (maternalBmi = 18.5 && maternalBmi = 25 && maternalBmi < 30) { bmiCategory = 'Overweight'; } else { bmiCategory = 'Obese'; } bmiCategoryElement.textContent = bmiCategory; // Simplified factors based on common research trends // These are illustrative and not Duke's exact proprietary formula var gestationalFactor = 1; if (gestationalAge 40) { gestationalFactor = 1.05 + (gestationalAge – 40) * 0.03; // Higher for post-term } else { gestationalFactor = 1.0; // Term } gestationalFactorElement.textContent = gestationalFactor.toFixed(2); var maternalWeightFactor = 1; if (maternalBmi = 25 && maternalBmi = 30) { maternalWeightFactor = 1.1; } else { maternalWeightFactor = 1.0; } maternalWeightFactorElement.textContent = maternalWeightFactor.toFixed(2); // Base prediction (example: average term baby weight) var baseWeight = 3400; // grams // Adjustments var predictedWeight = baseWeight; // Gestational Age Adjustment (simplified linear) predictedWeight += (gestationalAge – 39) * 150; // Add ~150g per week past 39, subtract for earlier // Maternal Height Adjustment predictedWeight += (maternalHeightCm – 165) * 30; // Add ~30g per cm over 165cm // Maternal Weight Adjustment (using BMI factor) predictedWeight *= maternalWeightFactor; // Diabetes Adjustment (significant increase) if (maternalDiabetes === 1) { predictedWeight *= 1.15; // Increase by 15% for diabetes } // Hypertension Adjustment (can be complex, simplified: slight reduction if severe) // In many models, hypertension can correlate with smaller babies due to placental issues. // For simplicity, we'll apply a small reduction if present. if (maternalHypertension === 1) { predictedWeight *= 0.97; // Slight reduction } // Previous Birth Weight Adjustment (if available) if (previousBirthWeightGrams > 0) { // Use a portion of the previous weight to influence prediction predictedWeight = predictedWeight * 0.6 + previousBirthWeightGrams * 0.4; } // Final Cap/Floor and Rounding predictedWeight = Math.max(500, Math.min(5000, predictedWeight)); // Cap between 500g and 5000g predictedWeight = Math.round(predictedWeight); predictedWeightElement.textContent = predictedWeight + ' grams'; var formulaText = "Estimated Birth Weight = (Base Weight + GA Adjustment + Height Adjustment) * Maternal Weight Factor"; if (maternalDiabetes === 1) formulaText += " * Diabetes Factor"; if (maternalHypertension === 1) formulaText += " * Hypertension Factor"; if (previousBirthWeightGrams > 0) formulaText += " (influenced by Previous Birth Weight)"; formulaExplanationElement.textContent = formulaText; updateChart(gestationalAge, maternalHeightCm, maternalWeightKg, maternalDiabetes, maternalHypertension, previousBirthWeightGrams, predictedWeight); } function resetCalculator() { document.getElementById('gestationalAge').value = 39; document.getElementById('maternalHeightCm').value = 165; document.getElementById('maternalWeightKg').value = 60; document.getElementById('maternalDiabetes').value = 0; document.getElementById('maternalHypertension').value = 0; document.getElementById('previousBirthWeightGrams').value = 3500; // Reset to a common value or blank if preferred // Clear errors var inputs = document.querySelectorAll('.loan-calc-container input, .loan-calc-container select'); inputs.forEach(function(input) { input.classList.remove('error-active'); if (input.nextElementSibling && input.nextElementSibling.classList.contains('error-message')) { input.nextElementSibling.style.display = 'none'; } }); calculateBirthWeight(); // Recalculate with default values } function copyResults() { var predictedWeight = predictedWeightElement.textContent; var bmiCategory = bmiCategoryElement.textContent; var gestationalFactor = gestationalFactorElement.textContent; var maternalWeightFactor = maternalWeightFactorElement.textContent; var formula = formulaExplanationElement.textContent; var resultsText = "— Birth Weight Prediction Results —\n\n"; resultsText += "Estimated Birth Weight: " + predictedWeight + "\n"; resultsText += "Maternal BMI Category: " + bmiCategory + "\n"; resultsText += "Gestational Factor: " + gestationalFactor + "\n"; resultsText += "Maternal Weight Factor: " + maternalWeightFactor + "\n"; resultsText += "Formula Used: " + formula + "\n\n"; resultsText += "Note: This is an estimate based on the Duke Birth Weight Predictor model. Consult your healthcare provider for personalized advice."; // Use a temporary textarea to copy to clipboard var textArea = document.createElement("textarea"); textArea.value = resultsText; textArea.style.position = "fixed"; textArea.style.left = "-9999px"; document.body.appendChild(textArea); textArea.focus(); textArea.select(); try { var successful = document.execCommand('copy'); var msg = successful ? 'Results copied!' : 'Copying failed'; alert(msg); } catch (err) { alert('Copying failed: ' + err); } document.body.removeChild(textArea); } function updateChart(gestationalAge, maternalHeightCm, maternalWeightKg, maternalDiabetes, maternalHypertension, previousBirthWeightGrams, predictedWeight) { var ctx = document.getElementById('birthWeightChart').getContext('2d'); // Define data series var labels = ['Gestational Age', 'Maternal Height', 'Maternal Weight', 'Diabetes', 'Hypertension', 'Prev. Birth Wt.']; var dataSeries1 = []; // Represents contribution/factor var dataSeries2 = []; // Represents baseline or adjusted value // Simplified contribution visualization // This is highly illustrative and not a precise breakdown of the formula's internal weights var baseWeight = 3400; var gaContribution = (gestationalAge – 39) * 150; var heightContribution = (maternalHeightCm – 165) * 30; var weightFactor = 1; var maternalBmi = maternalWeightKg / Math.pow(maternalHeightCm / 100, 2); if (maternalBmi = 25 && maternalBmi = 30) weightFactor = 1.1; else weightFactor = 1.0; var diabetesFactor = maternalDiabetes === 1 ? 1.15 : 1.0; var hypertensionFactor = maternalHypertension === 1 ? 0.97 : 1.0; var prevWtInfluence = 0; if (previousBirthWeightGrams > 0) { prevWtInfluence = previousBirthWeightGrams; } dataSeries1 = [ gaContribution, heightContribution, (weightFactor – 1) * 100, // Percentage change from baseline weight factor (diabetesFactor – 1) * 100, // Percentage change from baseline diabetes factor (hypertensionFactor – 1) * 100, // Percentage change from baseline hypertension factor (prevWtInfluence > 0 ? (prevWtInfluence – baseWeight) / baseWeight * 100 : 0) // Relative influence of previous weight ]; dataSeries2 = [ gestationalAge, maternalHeightCm, maternalWeightKg, maternalDiabetes, maternalHypertension, previousBirthWeightGrams > 0 ? previousBirthWeightGrams : 'N/A' ]; if (chart) { chart.destroy(); } chart = new Chart(ctx, { type: 'bar', // Use bar chart for better comparison of factors data: { labels: labels, datasets: [{ label: 'Factor Influence (%) / Value', data: dataSeries1, backgroundColor: 'rgba(0, 74, 153, 0.6)', // Primary color borderColor: 'rgba(0, 74, 153, 1)', borderWidth: 1 }, { label: 'Input Value', data: dataSeries2, backgroundColor: 'rgba(40, 167, 69, 0.6)', // Success color borderColor: 'rgba(40, 167, 69, 1)', borderWidth: 1 }] }, options: { responsive: true, maintainAspectRatio: false, scales: { y: { beginAtZero: false, // Allow negative values for influence title: { display: true, text: 'Factor Influence (%) / Input Value (grams/cm/kg)' } }, x: { title: { display: true, text: 'Input Factors' } } }, plugins: { title: { display: true, text: 'Contribution of Factors to Birth Weight Prediction' }, tooltip: { callbacks: { label: function(context) { var label = context.dataset.label || "; if (label) { label += ': '; } if (context.parsed.y !== null) { if (context.dataset.label === 'Factor Influence (%) / Value') { label += context.parsed.y.toFixed(1) + '%'; } else { label += context.parsed.y + (context.label === 'Maternal Height' ? ' cm' : (context.label === 'Maternal Weight' ? ' kg' : (context.label === 'Prev. Birth Wt.' ? ' g' : "))); } } return label; } } } } } }); } // Initial calculation on page load window.onload = function() { // Ensure canvas element exists before trying to get context var canvas = document.getElementById('birthWeightChart'); if (canvas) { chartContext = canvas.getContext('2d'); // Initialize chart with placeholder data or call updateChart directly updateChart(39, 165, 60, 0, 0, 3500, 3400); // Initial call with default values } calculateBirthWeight(); };

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