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Perinatology Wheel Method:
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The Pregnancy Wheel Calculator (Perinatology Wheel Method) estimates the due date based on the last menstrual period using the standard 280-day pregnancy duration. This method is widely used in clinical practice for pregnancy dating.
The calculator uses the Perinatology Wheel equation:
Where:
Explanation: This calculation assumes a regular 28-day menstrual cycle with ovulation occurring on day 14. The 280 days represent 40 weeks of gestation.
Details: Accurate due date estimation is crucial for proper prenatal care, monitoring fetal development, scheduling important tests, and planning 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 due date estimation. This method works best for women with regular menstrual cycles.
Q1: How accurate is the pregnancy wheel method?
A: The method is generally accurate for women with regular 28-day cycles. For irregular cycles, ultrasound dating in the first trimester may be more accurate.
Q2: What if I don't know my LMP exactly?
A: If you're unsure of your LMP, an early pregnancy ultrasound (before 14 weeks) can provide a reliable due date estimate based on fetal measurements.
Q3: Why 280 days instead of 9 months?
A: Pregnancy is calculated as 40 weeks from LMP, which equals 280 days. This accounts for the fact that pregnancy begins about 2 weeks before conception occurs.
Q4: Can my due date change during pregnancy?
A: Yes, healthcare providers may adjust the due date based on early ultrasound findings, especially if there's a significant difference from the LMP-based calculation.
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.