1. What is the EDD Pregnancy Calculator?

The EDD (Estimated Due Date) Pregnancy Calculator estimates your baby's due date based on your last menstrual period (LMP) following the standard NHS calculation method of adding 280 days (40 weeks) to the first day of your LMP.

2. How Does the Calculator Work?

The calculator uses the standard NHS formula:

Where:

• \( EDD \) — Estimated Due Date
• \( LMP \) — First day of Last Menstrual Period

Explanation: This calculation is based on Naegele's rule, assuming a 28-day menstrual cycle with ovulation occurring on day 14.

3. Importance of EDD Calculation

Details: Knowing your estimated due date helps healthcare providers monitor fetal growth, schedule important tests, and determine if pregnancy continues beyond term. The NHS uses this date to plan your antenatal care.

4. Using the Calculator

Tips: Enter the first day of your last menstrual period (LMP) in the format YYYY-MM-DD. The calculator will add 280 days (40 weeks) to determine your estimated due date.

5. Frequently Asked Questions (FAQ)

Q1: What if my cycle isn't 28 days?
A: The calculator assumes a 28-day cycle. If your cycle is longer or irregular, your actual due date may differ. An early ultrasound can provide a more accurate estimate.

Q2: 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 the calculated date.

Q3: What if I don't know my LMP?
A: If you're unsure of your LMP, your midwife or doctor can estimate your due date using an early ultrasound scan (dating scan).

Q4: Why does the NHS use this method?
A: It's a standardized method that works well for most women with regular cycles. Ultrasound dating is used when LMP is unknown or cycles are irregular.

Q5: Can the due date change?
A: Yes, your due date may be adjusted after your dating scan (usually between 8-14 weeks) if the ultrasound measurement differs significantly from the LMP-based calculation.