1. What is the Due Date Calculation?

The pregnancy due date is typically 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 delivery dates.

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. The actual delivery date may vary by ±2 weeks.

3. Importance of Due Date Estimation

Details: Accurate due date estimation is crucial for proper prenatal care, monitoring fetal development, and determining if pregnancy progresses normally or requires intervention.

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 to estimate your due date.

5. Frequently Asked Questions (FAQ)

Q1: 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.

Q2: What if my cycles aren't 28 days?
A: For irregular cycles or known ovulation dates, ultrasound dating in early pregnancy is more accurate.

Q3: Why 280 days from LMP?
A: Pregnancy is traditionally dated from LMP, which is about 2 weeks before conception typically occurs.

Q4: How does this compare to ultrasound dating?
A: First-trimester ultrasound is more accurate and may adjust the due date, especially if LMP date is uncertain.

Q5: What's considered full term?
A: 37-42 weeks is considered term. Before 37 weeks is preterm, after 42 weeks is post-term.