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Pregnancy Due Date Calculator

Due Date Calculation:

\[ \text{Due Date} = \text{LMP} + 280 \text{ days} \]

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1. What is the Pregnancy Due Date Calculator?

The Pregnancy Due Date Calculator estimates the expected delivery date based on the first day of the last menstrual period (LMP). This calculation follows Naegele's rule, which adds 280 days (40 weeks) to the LMP.

2. How Does the Calculator Work?

The calculator uses the standard formula:

\[ \text{Due Date} = \text{LMP} + 280 \text{ days} \]

Where:

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

3. Importance of Due Date Calculation

Details: An accurate due date helps monitor fetal development, schedule prenatal tests, and identify potential preterm or post-term pregnancies.

4. Using the Calculator

Tips: Enter the first day of your last menstrual period. The calculator will estimate your due date based on a standard 40-week pregnancy.

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.

Q2: What if my cycles aren't regular?
A: For irregular cycles, an early ultrasound provides more accurate dating than LMP-based calculations.

Q3: Does this work for IVF pregnancies?
A: For IVF, use the embryo transfer date + 266 days (or 263 days for day-3 embryos).

Q4: Why 280 days if pregnancy is 9 months?
A: Pregnancy is actually about 9.5 lunar months (40 weeks). Calendar months vary in length.

Q5: When will my doctor adjust my due date?
A: Doctors may adjust based on first-trimester ultrasound if it differs by >5-7 days from LMP date.

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