1. What is the Expected Date of Birth Calculation?

The expected date of birth (EDB), also known as the due date, is calculated as 280 days (40 weeks) from the first day of the last menstrual period (LMP). This is based on Naegele's rule, the standard method for estimating pregnancy due dates.

2. How Does the Calculator Work?

The calculator uses the standard pregnancy calculation:

Where:

• Last Menstrual Period — First day of the woman's last menstrual period
• 280 days — Equivalent to 40 weeks of gestation

Explanation: This calculation assumes a regular 28-day menstrual cycle with ovulation occurring on day 14. The actual delivery date may vary by ±2 weeks.

3. Importance of Due Date Calculation

Details: Accurate due date estimation is crucial for proper prenatal care, monitoring fetal development, and determining the optimal time for certain tests and interventions.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: How accurate is this due date calculation?
A: Only about 5% of women deliver on their exact due date. Most deliver within 2 weeks before or after the estimated date.

Q2: What if my menstrual cycle isn't 28 days?
A: For women with irregular cycles, an ultrasound measurement in early pregnancy often provides a more accurate due date.

Q3: Why is the calculation based on LMP rather than conception?
A: Most women know their LMP but not their exact conception date, making LMP the most practical starting point.

Q4: How does this compare to ultrasound dating?
A: First-trimester ultrasound dating is typically accurate to within 5-7 days and may adjust the LMP-based due date.

Q5: What if I don't remember my LMP?
A: If LMP is unknown, a healthcare provider can estimate gestational age through physical examination and ultrasound.