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LMP Se EDD Formula:
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The LMP Se EDD (Last Menstrual Period to Estimated Due Date) calculation is a standard method used in obstetrics to determine the expected delivery date of a pregnancy. It is based on Naegele's Rule, which adds 280 days (40 weeks) to the first day of the last menstrual period.
The calculator uses the standard obstetric formula:
Where:
Explanation: This calculation assumes a regular 28-day menstrual cycle and ovulation occurring on day 14. The 280 days represent 40 weeks of gestation from the LMP.
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 any 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 is EDD calculated from LMP rather than conception date?
A: LMP is typically more reliably remembered than conception date, and it provides a standardized reference point for healthcare providers worldwide.
Q2: How accurate is the LMP method?
A: The LMP method is accurate for women with regular 28-day cycles. For irregular cycles, ultrasound dating in the first trimester is more reliable.
Q3: What if I don't remember my LMP exactly?
A: If LMP is uncertain, an early pregnancy ultrasound (especially between 8-13 weeks) can provide a more accurate due date based on fetal measurements.
Q4: Can the due date change during pregnancy?
A: Yes, if early ultrasound measurements differ significantly from LMP-based dating, healthcare providers may adjust the EDD, particularly in the first trimester.
Q5: What percentage of babies are born exactly on their due date?
A: Only about 4-5% of babies are born on their exact due date. Most births occur within two weeks before or after the calculated EDD.