1. What is the Perinatology IVF Due Date Calculation?

The Perinatology method calculates IVF due dates by adding 266 days (38 weeks) to the embryo transfer date and subtracting the embryo's age in days. This method accounts for the exact conception date in IVF pregnancies, providing more accurate dating than standard pregnancy calculations.

2. How Does the Calculator Work?

The calculator uses the Perinatology formula:

Where:

• 266 days — Standard length of human pregnancy from conception (38 weeks)
• Embryo Age — Days of development at time of transfer (typically 3 or 5 days)

Explanation: This calculation method is more precise for IVF pregnancies because it uses the known embryo transfer date rather than estimating from the last menstrual period.

3. Importance of Accurate IVF Dating

Details: Accurate due date calculation is crucial for proper prenatal care timing, growth monitoring, and scheduling important tests and interventions in IVF pregnancies.

4. Using the Calculator

Tips: Enter the embryo transfer date and embryo age (typically 3 days for Day 3 embryos or 5 days for Day 5 blastocysts). The calculator will provide the estimated due date.

5. Frequently Asked Questions (FAQ)

Q1: Why 266 days 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.

Q2: What embryo age should I use?
A: Use 3 for Day 3 embryos, 5 for Day 5 blastocysts, or the actual embryo age if known.

Q3: Does this work for frozen embryo transfers?
A: Yes, use the actual transfer date of the frozen embryo and its age at freezing.

Q4: How accurate is this calculation?
A: This is the most accurate method for IVF pregnancies, though individual variations in pregnancy length still occur.

Q5: Should I adjust for my menstrual cycle length?
A: No adjustment needed - the calculation is based on the known embryo transfer date.