1. What is the Due Date Calculation?

The due date calculation estimates the expected date of delivery based on the first day of the last menstrual period (LMP). This is commonly known as Naegele's rule, which adds 280 days (40 weeks) to the LMP.

2. How Does the Calculator Work?

The calculator uses the standard formula:

Where:

• \( LMP \) — First day of last menstrual period
• \( 280\ days \) — Equivalent to 40 weeks gestation

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

3. Importance of Due Date Calculation

Details: Accurate due date estimation is crucial for prenatal care scheduling, monitoring fetal development, and determining if pregnancy is progressing normally.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: How accurate is this calculation?
A: It's an estimate - only about 5% of women deliver on their exact due date. Most deliver within 2 weeks before or after.

Q2: What if my cycles aren't 28 days?
A: The calculation may need adjustment. Consult your healthcare provider for a more accurate estimate based on your cycle length.

Q3: When should I confirm with ultrasound?
A: Early ultrasound (first trimester) provides the most accurate dating. Later ultrasounds are less reliable for dating.

Q4: What's considered full term?
A: 39-40 weeks is full term. 37-38 weeks is early term, and 41+ weeks is late term.

Q5: Can the due date change?
A: Yes, especially if early ultrasound measurements differ significantly from LMP-based estimates.