1. What is Estimated Due Date (EDD)?

The Estimated Due Date (EDD) is the calculated date when a pregnant woman is expected to deliver her baby. It's based on the first day of the last menstrual period (LMP) plus 280 days (40 weeks).

2. How Does the Calculator Work?

The calculator uses the Naegele's rule:

Where:

• \( LMP \) — First day of last menstrual period
• \( 280 \) — Standard length of pregnancy (40 weeks)

Explanation: This calculation assumes a regular 28-day menstrual cycle with ovulation occurring on day 14.

3. Importance of EDD Calculation

Details: The EDD helps healthcare providers monitor fetal growth, schedule important prenatal tests, and determine if pregnancy is progressing normally. It's also used to assess preterm or post-term status.

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

Q2: What if my cycles aren't 28 days long?
A: The calculation may need adjustment. Consult your healthcare provider who can adjust based on your cycle length or early ultrasound findings.

Q3: When is an ultrasound more accurate than LMP?
A: Early ultrasound (especially first trimester) can provide a more accurate EDD if the LMP date is uncertain or cycles are irregular.

Q4: Can the due date change?
A: Yes, healthcare providers may adjust the EDD based on ultrasound measurements, especially if there's a significant difference from the LMP-based calculation.

Q5: What's the difference between gestational age and fetal age?
A: Gestational age is calculated from LMP (about 2 weeks longer than fetal age which is calculated from conception).