1. What is the IVF Due Date Calculation?

The IVF due date calculation accounts for the age of the embryo at transfer, providing a more accurate due date than standard pregnancy calculations. It's based on the concept that pregnancy duration is 266 days from conception (38 weeks).

2. How Does the Calculator Work?

The calculator uses the IVF due date formula:

Where:

• Embryo Transfer Date — The date the embryo was transferred to the uterus
• Embryo Age — Number of days the embryo had developed before transfer (typically 3 for day-3 embryos or 5 for day-5 blastocysts)
• 266 days — Standard length of pregnancy from conception

Explanation: The calculation adjusts for the embryo's development prior to transfer to determine the actual conception date equivalent.

3. Importance of Accurate Due Date

Details: An accurate due date is crucial for proper prenatal care timing, monitoring fetal development, and planning for delivery. IVF pregnancies benefit from this precise calculation method.

4. Using the Calculator

Tips:

• Enter the exact date of embryo transfer
• Specify embryo age in days (typically 3 for day-3 embryos or 5 for day-5 blastocysts)
• For frozen embryo transfers, use the thaw/transfer date and original embryo age

5. Frequently Asked Questions (FAQ)

Q1: Why is 266 days used instead of 280 days?
A: 280 days (40 weeks) is calculated from the last menstrual period (LMP). 266 days (38 weeks) is the actual gestation period from conception, which is known in IVF.

Q2: What embryo age should I use for a blastocyst?
A: For day-5 blastocysts, enter 5 days. For day-3 embryos, enter 3 days.

Q3: Does this work for frozen embryo transfers?
A: Yes, use the transfer date and the original embryo age (days of development before freezing).

Q4: How accurate is this calculation?
A: Very accurate for IVF pregnancies, as the conception date is precisely known. Actual delivery may vary ±2 weeks from the calculated date.

Q5: Should I use LMP dating for IVF pregnancies?
A: No, LMP dating is less accurate for IVF pregnancies. Always use the IVF-specific calculation.