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Conception Calculation Formula:
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The Conception Date Calculator estimates the exact date of conception based on ultrasound dating. This calculation helps determine when pregnancy likely began using standard obstetric calculations.
The calculator uses the standard obstetric formula:
Where:
Explanation: This calculation accounts for the fact that pregnancy dating typically starts from the first day of the last menstrual period (LMP), with conception occurring approximately 2 weeks later.
Details: Accurate conception dating is crucial for proper prenatal care, determining due dates, monitoring fetal development, and planning for delivery. Ultrasound dating is considered one of the most reliable methods for establishing gestational age.
Tips: Enter the exact date of your ultrasound and the gestational age in weeks as reported by your healthcare provider. Ensure both values are accurate for the most precise conception date estimation.
Q1: How accurate is ultrasound for dating pregnancy?
A: First-trimester ultrasounds are highly accurate (±5-7 days), while second-trimester ultrasounds are accurate within ±10-14 days for dating purposes.
Q2: Why subtract 14 days in the calculation?
A: This accounts for the typical 2-week difference between the first day of the last menstrual period and actual conception in a regular 28-day cycle.
Q3: Can conception date be determined exactly?
A: While this calculator provides a close estimate, the exact moment of conception cannot be pinpointed with absolute certainty through ultrasound alone.
Q4: What if my cycle is irregular?
A: Ultrasound dating is particularly valuable for women with irregular cycles, as it doesn't rely on menstrual history for accurate dating.
Q5: When is the best time for dating ultrasound?
A: The most accurate dating occurs between 8-13 weeks gestation, when fetal measurements are most reliable for establishing gestational age.