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Due Date Calculation:
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The Due Date Calculator estimates the expected delivery date based on the first day of your last menstrual period (LMP), adding 280 days (40 weeks). This is known as Naegele's rule, the standard method for pregnancy dating.
The calculator uses the standard obstetric formula:
Where:
Explanation: The calculation assumes a regular 28-day menstrual cycle with ovulation occurring on day 14. The calculator also shows current progress and gestational age.
Details: Accurate due date estimation is crucial for proper prenatal care, monitoring fetal development, and planning for delivery. It helps identify preterm or post-term pregnancies that may need special attention.
Tips: Enter the first day of your last menstrual period (LMP) in the format YYYY-MM-DD. The calculator will show your estimated due date, current progress percentage, and gestational age in weeks and days.
Q1: How accurate is this due date calculation?
A: The calculation is accurate for women with regular 28-day cycles. Ultrasound dating in the first trimester may provide a more accurate estimate if LMP is uncertain.
Q2: What if my cycles aren't 28 days?
A: For irregular or longer cycles, the due date may need adjustment. Consult your healthcare provider for a more personalized estimate.
Q3: What percentage of babies are born on their due date?
A: Only about 5% of women deliver on their exact due date. Most deliver within 2 weeks before or after.
Q4: How does this differ from conception date?
A: Conception typically occurs about 2 weeks after LMP, so the fetal age is about 2 weeks less than the gestational age.
Q5: Can the due date change?
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.