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Pregnancy EDD Formula:
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The Pregnancy EDD (Estimated Due Date) calculation estimates the expected delivery date based on the last menstrual period. It uses Naegele's rule: LMP + 280 days (40 weeks), which is the standard method for estimating due dates in obstetrics.
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 represents 40 weeks of gestation.
Details: Accurate EDD calculation is crucial for proper 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 EDD estimation. The calculator will provide the estimated due date based on standard obstetric calculations.
Q1: How Accurate Is The EDD Calculation?
A: The EDD is an estimate - only about 5% of women deliver on their exact due date. Most deliveries occur within 2 weeks before or after the calculated date.
Q2: What If My Menstrual Cycle Is Not 28 Days?
A: For women with irregular or longer cycles, the EDD may need adjustment. Ultrasound dating in early pregnancy often provides a more accurate estimate.
Q3: When Should I Confirm My EDD With Ultrasound?
A: Early ultrasound (8-13 weeks) is recommended to confirm dating, especially if LMP is uncertain or cycles are irregular.
Q4: Can The EDD Change During Pregnancy?
A: Yes, healthcare providers may adjust the EDD based on ultrasound measurements, particularly if there's a significant discrepancy from LMP-based calculation.
Q5: What Are The Limitations Of This Calculation?
A: This method assumes regular ovulation and may be less accurate for women with irregular cycles, recent hormonal contraception use, or uncertain LMP dates.