1. What is the IVF FET Due Date Calculation?

The IVF FET (Frozen Embryo Transfer) due date calculation estimates the expected delivery date based on the transfer date and the age of the embryo at transfer. This method provides a more accurate due date than traditional last menstrual period calculations for IVF pregnancies.

2. How Does the Calculator Work?

The calculator uses the following formula:

Where:

• FET Date — Date of the frozen embryo transfer
• Embryo Age — Number of days the embryo was developed before freezing (typically 3 for day-3 embryos or 5 for day-5 blastocysts)
• 266 days — Standard length of human pregnancy from conception

Explanation: The calculation accounts for the embryo's development prior to transfer, adjusting the due date accordingly.

3. Importance of Accurate Due Date Calculation

Details: Accurate due dating is crucial for proper prenatal care scheduling, fetal growth assessment, and timing of important tests and interventions during pregnancy.

4. Using the Calculator

Tips: Enter the exact date of embryo transfer and the embryo's age in days (typically 3 or 5 days for most IVF procedures).

5. Frequently Asked Questions (FAQ)

Q1: Why 266 days instead of 280 days?
A: 280 days is calculated from the last menstrual period (LMP), while 266 days is from conception. IVF provides the exact conception date.

Q2: What's the difference between day-3 and day-5 embryos?
A: Day-3 embryos are at cleavage stage (6-8 cells), while day-5 embryos are blastocysts with hundreds of cells. Their due dates differ by 2 days.

Q3: Does this work for fresh embryo transfers?
A: Yes, the same calculation applies, though fresh transfers may have slightly different timing considerations.

Q4: How accurate is this due date?
A: IVF due dates are more accurate than LMP-based dates, but individual variations in pregnancy length still occur.

Q5: Should I adjust for my menstrual cycle length?
A: No, IVF calculations don't require cycle length adjustments as the conception date is known precisely.