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EDD Gestation Formula:
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The Due Date Calculator Weeks Gestation estimates the expected delivery date (EDD) based on the last menstrual period (LMP) and calculates current gestational age in weeks and days. This follows the standard obstetric practice of adding 280 days (40 weeks) to the LMP.
The calculator uses the standard gestation formula:
Where:
Explanation: The calculation assumes a regular 28-day menstrual cycle and ovulation occurring on day 14. Current gestation is calculated from LMP to current date.
Details: Accurate due date estimation is essential for prenatal care planning, fetal growth monitoring, timing of prenatal tests, and preparing for delivery. It helps healthcare providers track pregnancy progression 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 precise due date estimation. The calculator will display both the estimated due date and current gestational age.
Q1: How Accurate Is The LMP Method?
A: The LMP method is generally accurate for women with regular 28-day cycles. Ultrasound dating in the first trimester may provide more precise dating if LMP is uncertain.
Q2: What If My Cycle Is Not 28 Days?
A: For cycles longer or shorter than 28 days, adjustments may be needed. Consult with your healthcare provider for cycle-length specific calculations.
Q3: When Should I Confirm With Ultrasound?
A: Early pregnancy ultrasound (6-12 weeks) can confirm dating. First-trimester ultrasound is most accurate for establishing gestational age.
Q4: Can The Due Date Change?
A: Yes, due dates may be adjusted based on early ultrasound findings or if fetal measurements don't match LMP-based calculations.
Q5: What Percentage Of Babies Are Born On Their Due Date?
A: Only about 5% of babies are born exactly on their due date. Most births occur within two weeks before or after the estimated due date.