1. What is NHS EDD Calculator?

The NHS EDD (Estimated Due Date) Calculator estimates the expected delivery date based on the last menstrual period using the standard NHS calculation method. It follows the formula: EDD = LMP + 280 days.

2. How Does the Calculator Work?

The calculator uses the NHS standard formula:

Where:

• \( EDD \) — Estimated Due Date
• \( LMP \) — Last Menstrual Period date
• \( 280 \text{ days} \) — Standard pregnancy duration (40 weeks)

Explanation: This calculation assumes a regular 28-day menstrual cycle and counts from the first day of the last menstrual period, which is approximately 2 weeks before conception typically occurs.

3. Importance of EDD Calculation

Details: Accurate due date estimation is crucial for proper prenatal care scheduling, fetal development monitoring, and planning for delivery. It helps healthcare providers track pregnancy milestones and identify 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 also show current gestation in days.

5. Frequently Asked Questions (FAQ)

Q1: How accurate is the LMP method?
A: The LMP method is generally accurate for women with regular 28-day cycles. For irregular cycles, ultrasound dating in early pregnancy may be more reliable.

Q2: What if I don't know my LMP exactly?
A: If you're unsure of your LMP, an early pregnancy ultrasound (before 14 weeks) can provide a more accurate due date estimation.

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 my due date change?
A: Yes, healthcare providers may adjust the due date based on early ultrasound measurements or if the LMP-based date differs significantly from ultrasound findings.

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 2 weeks before or after the estimated due date.