1. What is the Pregnancy Calculator Wheel?

The Pregnancy Calculator Wheel, also known as a gestation calculator or pregnancy wheel, is a clinical tool used to estimate the due date of pregnancy based on the last menstrual period (LMP). It follows Naegele's rule, adding 280 days (40 weeks) to the first day of the LMP.

2. How Does the Calculator Work?

The calculator uses the standard pregnancy wheel formula:

Where:

• \( LMP \) — First day of last menstrual period
• \( 280\ days \) — Standard duration of human pregnancy (40 weeks)

Explanation: This calculation assumes a regular 28-day menstrual cycle and ovulation occurring on day 14. The due date represents the estimated date of delivery (EDD).

3. Importance of Due Date Calculation

Details: Accurate due date estimation is crucial for proper prenatal care, monitoring fetal development, scheduling important tests, and determining gestational age for delivery planning.

4. Using the Calculator

Tips: Enter the first day of your last menstrual period in the date field. Ensure the date is accurate for the most reliable due date estimation.

5. Frequently Asked Questions (FAQ)

Q1: How accurate is the pregnancy wheel calculation?
A: The pregnancy wheel provides a good estimate, but only about 5% of women deliver exactly on their due date. Most deliveries occur within 2 weeks before or after the estimated date.

Q2: What if my menstrual cycle is irregular?
A: For women with irregular cycles, an early ultrasound (first trimester) provides a more accurate due date estimation than LMP-based calculations.

Q3: Why 280 days specifically?
A: 280 days represents 40 weeks of gestation, calculated from the first day of the last menstrual period, which includes approximately 2 weeks before conception actually occurs.

Q4: Can the due date change during pregnancy?
A: Yes, healthcare providers may adjust the due date based on early ultrasound measurements, especially if there's a significant discrepancy with the LMP-based calculation.

Q5: What's the difference between gestational age and fetal age?
A: Gestational age is calculated from the LMP (about 2 weeks longer than fetal age), while fetal age (conceptual age) is calculated from the actual date of conception.