1. What is EDD Calculation?

The Estimated Due Date (EDD) calculation is a basic pregnancy calculation method that determines the expected delivery date by adding 280 days (40 weeks) to the first day of the last menstrual period (LMP).

2. How Does the Calculator Work?

The calculator uses the standard EDD formula:

Where:

• \( EDD \) — Estimated Due Date
• \( LMP \) — Last Menstrual Period (first day)
• \( 280 \) — Standard pregnancy duration in days

Explanation: This calculation assumes a regular 28-day menstrual cycle and ovulation occurring on day 14. The 280 days represent 40 weeks of gestation.

3. Importance of EDD Calculation

Details: Accurate EDD calculation is crucial for monitoring fetal development, scheduling prenatal care, preparing for delivery, and identifying potential preterm or post-term pregnancies.

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 280-day calculation?
A: This method provides a general estimate. Only about 5% of women deliver exactly on their EDD, but most deliver within 2 weeks before or after.

Q2: What if my menstrual cycle is irregular?
A: For irregular cycles, early ultrasound dating is more accurate than LMP-based calculation.

Q3: Why 280 days instead of 9 months?
A: Pregnancy is calculated as 40 weeks from LMP, which equals 280 days. This accounts for the fact that conception typically occurs about 2 weeks after LMP.

Q4: Can EDD change during pregnancy?
A: Yes, EDD may be adjusted based on ultrasound measurements, especially if there's a significant difference from LMP-based calculation.

Q5: What is Naegele's Rule?
A: This calculation is based on Naegele's Rule: add 7 days to LMP, then subtract 3 months, and add 1 year.