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Pregnancy Calculation Formula:
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The pregnancy delivery date calculator estimates the due date and tracks weekly progress based on the last menstrual period (LMP). It follows the standard medical calculation of adding 280 days (40 weeks) to the first day of the last menstrual period.
The calculator uses the following formulas:
Where:
Explanation: The calculation assumes a 28-day menstrual cycle and ovulation occurring on day 14. The 280 days represent 40 weeks of gestation from the LMP.
Details: Accurate pregnancy dating is crucial for monitoring fetal development, scheduling prenatal tests, and preparing for delivery. It helps healthcare providers track appropriate growth milestones and identify potential complications.
Tips: Enter the first day of your last menstrual period and the current date (or any date you want to check). The calculator will provide your estimated due date, current pregnancy week, and progress percentage.
Q1: How accurate is the estimated due date?
A: The EDD is an estimate - only about 5% of women deliver exactly on their due date. Most deliveries occur within 2 weeks before or after the estimated date.
Q2: What if I have irregular periods?
A: For women with irregular cycles, an early ultrasound (first trimester) provides more accurate dating than LMP-based calculation.
Q3: Why 280 days from LMP instead of conception date?
A: LMP is used because most women know their last period date, while conception date is often uncertain. It adds about 2 weeks before actual conception.
Q4: How are pregnancy weeks calculated?
A: Pregnancy is calculated in completed weeks and days. Week 1 starts from the first day of your last menstrual period.
Q5: When should I confirm with a healthcare provider?
A: Always confirm pregnancy dating with your healthcare provider, who may adjust based on ultrasound measurements and clinical assessment.