1. What is the Reverse Due Date Calculator?

The Reverse Due Date Calculator calculates the number of weeks between conception date and due date. This helps estimate gestational age and verify pregnancy dating.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• Due Date — Estimated date of delivery (EDD)
• Conception Date — Estimated date of conception

Explanation: The calculator computes the difference in days between the two dates and converts it to weeks by dividing by 7.

3. Importance of Pregnancy Dating

Details: Accurate pregnancy dating is crucial for proper prenatal care, timing of tests, and determining if the pregnancy is progressing normally.

4. Using the Calculator

Tips: Enter both dates in the format YYYY-MM-DD. The conception date is typically about 2 weeks before the first missed period in a 28-day cycle.

5. Frequently Asked Questions (FAQ)

Q1: How accurate is this calculation?
A: It provides a mathematical estimate but may not account for variations in ovulation timing or fetal development.

Q2: What's the typical weeks between conception and due date?
A: Normally about 38 weeks (266 days) from conception to due date, or 40 weeks from last menstrual period.

Q3: Why is there a 2-week difference between LMP and conception dating?
A: Pregnancy dating traditionally starts from the first day of the last menstrual period (LMP), which is typically about 2 weeks before conception.

Q4: Can this be used for IVF pregnancies?
A: For IVF, conception date is precisely known, making this calculation more accurate than for natural conceptions.

Q5: What if my cycle isn't 28 days?
A: The calculation may need adjustment as ovulation timing varies with cycle length.