1. What is the Pregnancy Due Date Calculator?

The Pregnancy Due Date Calculator estimates the expected date of birth (EDD) based on the last menstrual period (LMP). This calculation uses the standard method of adding 280 days (40 weeks) to the first day of the last menstrual period.

2. How Does the Calculator Work?

The calculator uses the standard pregnancy formula:

Where:

• \( EDD \) — Expected Date of Birth (Due Date)
• \( LMP \) — Last Menstrual Period (first day)
• \( 280 \) — Standard pregnancy duration in days (40 weeks)

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

3. Importance of Due Date Calculation

Details: Accurate due date calculation is crucial for monitoring fetal development, scheduling prenatal care, preparing for delivery, and identifying potential pregnancy complications. It helps healthcare providers track appropriate fetal growth and development milestones.

4. Using the Calculator

Tips: Enter the first day of your last menstrual period in the date field. Ensure the date is accurate as this forms the basis for all subsequent pregnancy dating. The calculator will provide both your last menstrual period date and the calculated expected due date.

5. Frequently Asked Questions (FAQ)

Q1: How accurate is the 280-day calculation?
A: This method provides an estimate. Only about 5% of women deliver exactly on their due date. Most deliveries occur within 2 weeks before or after the calculated date.

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

Q3: Why is pregnancy dated from LMP rather than conception?
A: LMP is used because most women can recall their last period date more accurately than conception date. This creates a standardized method for pregnancy dating.

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 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. Our calculator uses the equivalent 280-day method for simplicity.