1. What is Pregnancy Due Date Calculation?

The pregnancy due date is calculated as 280 days (40 weeks) from the first day of the last menstrual period (LMP). This is known as Naegele's rule and is the standard method for estimating due dates in obstetrics.

2. How Does the Calculator Work?

The calculator uses two simple formulas:

Where:

• \( LMP \) — First day of last menstrual period
• \( Current\ Date \) — Today's date or any date you want to check
• 280 days — Standard length of human pregnancy (40 weeks)

Explanation: The calculation assumes a regular 28-day menstrual cycle with ovulation occurring on day 14. 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 if pregnancy is progressing normally.

4. Using the Calculator

Tips: Enter the first day of your last menstrual period and the current date (defaults to today). The calculator will show your estimated due date and current weeks/days pregnant.

5. Frequently Asked Questions (FAQ)

Q1: How accurate is the due date calculation?
A: 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: Why is LMP used instead of conception date?
A: LMP is more reliably known than conception date for most women and has been the standard for over 200 years.

Q4: When will my doctor adjust my due date?
A: Ultrasound measurements in the first trimester may lead to due date adjustments if they differ significantly from LMP-based calculation.

Q5: What's the difference between gestational age and fetal age?
A: Gestational age counts from LMP (about 2 weeks before conception), while fetal age counts from actual conception.