1. What is NSW EDD Calculation?

The NSW EDD (Estimated Due Date) calculation determines the expected delivery date based on the last menstrual period (LMP). This method adds 280 days (40 weeks) to the first day of the last menstrual period, following standard obstetric practice in New South Wales.

2. How Does the Calculator Work?

The calculator uses the NSW EDD formula:

Where:

• \( EDD \) — Estimated Due Date
• \( LMP \) — Last Menstrual Period (first day)
• \( 280 \) — Standard gestation period in days (40 weeks)

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

3. Importance of Due Date Calculation

Details: Accurate due date calculation is essential for proper prenatal care, monitoring fetal development, scheduling important tests and screenings, and preparing for delivery. It helps healthcare providers track pregnancy progress and identify any potential complications.

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. The calculator will automatically compute your estimated due date based on the standard 280-day gestation period.

5. Frequently Asked Questions (FAQ)

Q1: How accurate is the LMP method for due date calculation?
A: The LMP method is generally accurate for women with regular 28-day cycles. For irregular cycles or uncertain dates, ultrasound dating in the first trimester provides more accurate estimation.

Q2: What if I don't know my exact LMP?
A: If you're unsure of your LMP, an early pregnancy ultrasound (usually between 8-12 weeks) can provide a reliable due date based on fetal measurements.

Q3: Why 280 days instead of 9 months?
A: Pregnancy is calculated as 40 weeks from LMP, which equals 280 days. This differs from calendar months due to varying month lengths and provides a more precise measurement.

Q4: Can my due date change during pregnancy?
A: Yes, healthcare providers may adjust the due date based on early ultrasound findings, especially if there's a significant discrepancy between LMP and ultrasound dating.

Q5: What percentage of babies are born on their due date?
A: Only about 5% of babies are born exactly on their due date. Most births occur within two weeks before or after the estimated due date.