IVF Due Date Calculator
Estimate your due date after IVF embryo transfer.
Supports both Day 3 and Day 5 (blastocyst) transfers with accurate date calculations.
IVF due date calculation differs from natural conception dating because the exact fertilization date is known. This eliminates the uncertainty of standard Naegele’s Rule, making IVF due dates more precise.
The Formulas:
For Day-3 Embryo Transfer: Due Date = Transfer Date + 263 days
For Day-5 Blastocyst Transfer (most common): Due Date = Transfer Date + 261 days
Why the Difference? In a natural cycle, the embryo implants 6–10 days after ovulation (equivalent to day 5–9 of embryo development). In IVF, a day-5 blastocyst is already 5 days old at transfer, so you subtract 5 days from the standard 266-day embryo development period.
Comparison with Naegele’s Rule:
Standard pregnancies use: Due Date = LMP + 280 days (40 weeks)
IVF Day-5 transfer: Due Date = Transfer date + 261 days ≈ LMP + 280 days (if ovulation was on day 14)
Worked Example:
Day-5 blastocyst transfer on March 15, 2025:
Due date = March 15 + 261 days = November 30, 2025
Gestational age at transfer: 2 weeks + 5 days (doctors count pregnancy from 2 weeks before fertilization by convention).
Trimester Milestones from Transfer Date (Day-5):
- End of first trimester: Transfer + 75 days
- End of second trimester: Transfer + 168 days
- Full term (37 weeks): Transfer + 222 days
Practical Tips:
- Always confirm your due date with your reproductive endocrinologist — they track exact cycle day
- Frozen embryo transfer (FET) uses the same calculation as fresh transfer
- Twins from IVF are often delivered at 36–38 weeks — your OB may adjust the target date