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Pregnancy Calculation Formula:
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The Due Date Calculator estimates your expected delivery date and current pregnancy week based on your last menstrual period. It provides a week-by-week calendar to track your pregnancy progress.
The calculator uses standard pregnancy calculation formulas:
Where:
Explanation: The calculation assumes a 40-week pregnancy (280 days) from the first day of your last menstrual period, following standard obstetric practice.
Details: Accurate pregnancy dating is crucial for monitoring fetal development, scheduling prenatal tests, and preparing for delivery. It helps healthcare providers track growth milestones and identify potential issues early.
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 and current pregnancy week.
Q1: How accurate is the due date calculation?
A: The calculation is based on standard 40-week pregnancy duration. Actual delivery dates can vary by ±2 weeks, with only about 5% of women delivering exactly on their due date.
Q2: What if I don't know my LMP?
A: If you're unsure of your LMP, an ultrasound in early pregnancy can provide more accurate dating based on fetal measurements.
Q3: Why is pregnancy calculated from LMP instead of conception?
A: LMP is used because it's typically easier to recall than conception date. This creates a standardized method used by healthcare providers worldwide.
Q4: How do pregnancy weeks work?
A: Pregnancy is measured in completed weeks and days. For example, "12 weeks and 3 days" means you've completed 12 full weeks and are in your 13th week of pregnancy.
Q5: Can the due date change during pregnancy?
A: Yes, early ultrasound measurements may lead to adjustment of the due date, especially if there's a significant difference from the LMP-based calculation.