Due Date Calculator

Understanding Due Date Calculation

The Due Date Calculator is a comprehensive tool that helps expectant mothers and healthcare providers determine the estimated date of delivery (EDD). This calculator uses various methods to provide accurate predictions based on different starting points of pregnancy.

Methods of Due Date Calculation

Last Menstrual Period (LMP) Method

The most common method uses Naegele's rule, which calculates the due date by:

• Adding 7 days to the first day of your last menstrual period
• Counting back 3 months
• Adding 1 year

This calculation assumes a 28-day menstrual cycle and ovulation occurring on day 14.

Conception Date Method

If you know your conception date, the calculator:

• Adds 266 days to the conception date
• Provides a more accurate estimate if conception date is known
• Accounts for actual fertilization timing

IVF Transfer Method

For IVF pregnancies, the calculator considers:

• The embryo transfer date
• The age of the embryo at transfer (3, 5, or 6 days)
• Provides the most accurate due date prediction

Important Pregnancy Milestones

Understanding key dates helps you prepare for important pregnancy events:

• First Trimester Screening: 11-13 weeks
• Second Trimester Screening: 15-20 weeks
• Anatomy Scan: 18-22 weeks
• Glucose Screening: 24-28 weeks
• Group B Strep Test: 35-37 weeks
• Full Term: 37 weeks
• Due Date: 40 weeks

Understanding Due Date Accuracy

It's essential to note that:

• Only 5% of babies are born on their exact due date
• Normal delivery can occur between 37-42 weeks
• Due dates are estimates, not exact predictions
• Regular prenatal care is essential for monitoring pregnancy progress