HCG Doubling Calculations

HCG Doubling Calculations

The HCG AI application tracks the progression of Human Chorionic Gonadotropin (β-hCG) levels to provide insights into early pregnancy development. By analyzing the rate at which HCG levels increase over time, the system identifies trends that may indicate a healthy progression, a potential miscarriage, or an ectopic pregnancy.

Understanding Doubling Time

In a typical early pregnancy, HCG levels generally double every 48 to 72 hours. As the pregnancy progresses and HCG levels exceed 6,000 mIU/mL, the doubling rate often slows down.

The application calculates the Doubling Time (T₂) using the following logarithmic formula:

T₂ = (t₂ - t₁) * log(2) / [log(HCG₂) - log(HCG₁)]

• t₁, t₂: The timestamps of the first and second blood tests.
• HCG₁, HCG₂: The HCG values (mIU/mL) at those respective times.

Logging HCG Entries

To generate doubling calculations, you must log at least two HCG blood test results.

Via the Web Interface

1. Navigate to the Home tab.
2. Enter the HCG Value (mIU/mL) and the Date the blood was drawn.
3. (Optional) Enable Advanced details to provide your Last Menstrual Period (LMP) or Ovulation Date. This allows the AI to calculate the "Expected" HCG range for your specific gestational age.
4. Click Save Entry.

Via the API

You can programmatically add entries to the tracking engine:

Endpoint: POST /api/hcg-entries

Request Body:

{
  "date": "2023-10-25",
  "hcgValue": 450,
  "units": "mIU/mL",
  "lmpDate": "2023-09-20",
  "cycleLength": 28,
  "notes": "First blood test"
}

Analysis & Risk Assessment

Once multiple entries exist, the system generates an analysis within the Analysis tab. The "Medical Risk Assessment" engine categorizes results into three levels:

| Risk Level | Description | Typical Indication | | :--- | :--- | :--- | | LOW | HCG is doubling within the 48-72 hour window. | Normal intrauterine pregnancy progression. | | MEDIUM | Doubling time is slower than 72 hours but still increasing. | May require closer monitoring or an early ultrasound to confirm location. | | HIGH | HCG levels are declining, plateauing, or rising extremely slowly. | Potential risk of biochemical pregnancy, miscarriage, or ectopic pregnancy. |

Advanced Contextual Adjustments

The calculation logic becomes more precise when providing "Advanced Details":

• LMP & Cycle Length: If you provide your Last Menstrual Period and average cycle length (typically 21–45 days), the app calculates your Gestational Age.
• Ovulation Date: If known, this is the most accurate metric for HCG comparison, as it bypasses the variability of follicular phase lengths.
• Z-Scores: The system calculates Z-scores to compare your specific HCG value against clinical median values for your exact day of pregnancy.

Usage Example: Retrieving Calculations

To fetch the history and let the frontend visualize the doubling curve:

async function getHcgProgression() {
  const response = await fetch('/api/hcg-entries');
  const entries = await response.json();
  
  // Sort entries by date to visualize the trend
  const sortedEntries = entries.sort((a, b) => new Date(a.date) - new Date(b.date));
  
  console.log('HCG Trend:', sortedEntries);
}

[!IMPORTANT] Medical Disclaimer: These calculations are for educational and tracking purposes only. HCG doubling rates vary significantly between individuals. All results should be reviewed by a qualified healthcare professional.