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Pregnancy Calculation Formula:
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The Pregnancy Calculator Med estimates the expected due date (EDD) based on the last menstrual period (LMP) using the standard medical formula of adding 280 days. This provides healthcare professionals with an accurate assessment of pregnancy duration and expected delivery date.
The calculator uses the standard pregnancy calculation formula:
Where:
Explanation: This calculation is based on Naegele's rule, which assumes a 40-week gestation period from the first day of the last menstrual period.
Details: Accurate due date estimation is crucial for prenatal care planning, 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 as this forms the basis for all subsequent pregnancy dating and monitoring.
Q1: Why use 280 days instead of 9 months?
A: 280 days corresponds to 40 weeks, which is the standard medical calculation for pregnancy duration from LMP, accounting for the fact that pregnancy is measured from the first day of the last period, not conception.
Q2: How accurate is this calculation?
A: This method is accurate for women with regular 28-day cycles. For irregular cycles, ultrasound dating in the first trimester may provide more accurate results.
Q3: What if I don't know my LMP?
A: If LMP is unknown, an early pregnancy ultrasound (before 14 weeks) can provide the most accurate dating based on fetal measurements.
Q4: Does this account for leap years?
A: Yes, the calculator automatically accounts for leap years and varying month lengths when adding 280 days to the LMP date.
Q5: Can EDD change during pregnancy?
A: Yes, EDD may be adjusted based on first-trimester ultrasound measurements, which can be more accurate than LMP-based calculations in some cases.