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EDD Calculation Formula:
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The Estimated Due Date (EDD) calculation estimates the expected date of delivery based on the first day of the last menstrual period (LMP). This method, known as Naegele's rule, adds 280 days (40 weeks) to the LMP date.
The calculator uses the standard EDD formula:
Where:
Explanation: This calculation assumes a regular 28-day menstrual cycle and ovulation occurring on day 14. The 280 days represents the average human gestation period.
Details: Accurate EDD calculation is crucial for prenatal care, monitoring fetal development, scheduling important tests, and preparing for delivery. It helps healthcare providers track pregnancy progress and identify potential complications.
Tips: Enter the first day of your last menstrual period in the date field. Ensure the date is accurate for the most reliable estimation. The calculator will provide the estimated due date based on standard obstetric calculations.
Q1: How accurate is the LMP method?
A: The LMP method is generally accurate for women with regular 28-day cycles. For irregular cycles, ultrasound dating in early pregnancy may be more precise.
Q2: What if my cycle is longer or shorter than 28 days?
A: For cycles longer than 28 days, add the extra days to the EDD. For shorter cycles, subtract the difference. Alternatively, use ultrasound dating for greater accuracy.
Q3: Why 280 days instead of 9 months?
A: Pregnancy is calculated as 40 weeks from LMP, which equals 280 days. This differs from calendar months due to varying month lengths.
Q4: When is the best time to calculate EDD?
A: Calculate EDD as soon as pregnancy is confirmed, preferably during the first prenatal visit for optimal pregnancy monitoring.
Q5: Can EDD change during pregnancy?
A: Yes, EDD may be adjusted based on early ultrasound measurements, which can provide more accurate dating, especially if there's discrepancy with LMP-based calculation.