1. What is the Estimated Due Date?

The estimated due date (EDD) is the approximate date when a pregnant woman is expected to deliver. It's calculated as 280 days (40 weeks) from the first day of the last menstrual period (LMP), known as Naegele's rule.

2. How Does the Calculator Work?

The calculator uses the standard perinatal calculation:

Where:

• LMP — First day of last menstrual period
• 280 days — Equivalent to 40 weeks gestation

Explanation: This calculation assumes a regular 28-day menstrual cycle with ovulation occurring on day 14. The calculator also shows current gestational age based on today's date.

3. Importance of Due Date Calculation

Details: Accurate due date estimation is crucial for proper prenatal care, monitoring fetal development, scheduling tests, and determining if pregnancy is post-term.

4. Using the Calculator

Tips: Enter the first day of your last menstrual period. The calculator will show the estimated due date and current gestational age.

5. Frequently Asked Questions (FAQ)

Q1: How accurate is this calculation?
A: Only about 5% of women deliver on their exact due date. Most deliver within 2 weeks before or after.

Q2: What if my cycles aren't 28 days?
A: For irregular cycles, ultrasound dating in early pregnancy is more accurate than LMP-based calculation.

Q3: Why 280 days if pregnancy is 9 months?
A: Pregnancy is actually about 9.5 lunar months (4 weeks each). 280 days = 40 weeks = 9 months + 1 week.

Q4: When should I contact my doctor?
A: If you go beyond 41 weeks or if there are any concerns about fetal movement, bleeding, or contractions.

Q5: Can the due date change?
A: Yes, early ultrasound may adjust the due date, especially if it differs significantly from LMP calculation.