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EDD Calculation Formula:
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The Expected Due Date (EDD) calculated from conception date provides an accurate estimate of when a baby is likely to be born. This method adds 266 days (38 weeks) to the known conception date, representing the typical human gestation period from conception.
The calculator uses the simple formula:
Where:
Explanation: This calculation assumes a standard 38-week pregnancy duration from the actual date of conception, providing a more precise due date than calculations based on last menstrual period.
Details: Accurate due date calculation is essential for proper prenatal care, monitoring fetal development, planning for delivery, and ensuring the health of both mother and baby throughout pregnancy.
Tips: Enter the exact conception date if known. This method is most accurate when the conception date is certain, such as with fertility treatments or careful cycle tracking.
Q1: Why 266 days instead of 280 days?
A: 280 days is calculated from the last menstrual period (LMP), while 266 days is from actual conception. Pregnancy is typically 38 weeks from conception or 40 weeks from LMP.
Q2: How accurate is conception date calculation?
A: When the conception date is known with certainty, this method is highly accurate. However, only about 5% of babies are born exactly on their due date.
Q3: What if I don't know my conception date?
A: If conception date is unknown, use the last menstrual period (LMP) method by adding 280 days to the first day of your last period.
Q4: Can the due date change during pregnancy?
A: Yes, healthcare providers may adjust the due date based on ultrasound measurements, especially if early ultrasound dating differs significantly from calculated dates.
Q5: What is considered full term?
A: Full term is between 39 weeks 0 days and 40 weeks 6 days. Early term is 37 weeks 0 days through 38 weeks 6 days.