IVF Due Date Calculator – Estimate Delivery Date from Transfer
Estimated Due Date
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Gestational Age Today
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Equivalent LMP Date
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Trimester Timeline
Key Milestones
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Understanding IVF Due Date Calculation
An IVF due date is calculated differently from a natural conception due date because the exact timing of fertilization is known. In natural conception, due dates are estimated from the last menstrual period (LMP), which assumes ovulation occurred on day 14. With IVF, we know the precise embryo age.
The calculation works by determining the theoretical LMP date first. For a Day 5 blastocyst transfer, the LMP equivalent is the transfer date minus 19 days (14 days for the follicular phase plus 5 days of embryo age). The due date is then 280 days (40 weeks) from this LMP date. For Day 3 transfers, subtract 17 days instead.
Keep in mind that only about 5% of babies arrive on their exact due date. Most births occur within two weeks before or after the due date. Your healthcare provider may adjust your due date based on early ultrasound measurements. Regular prenatal appointments are essential throughout pregnancy.
Frequently Asked Questions
How is an IVF due date calculated?
For IVF pregnancies, the due date is calculated from the embryo transfer date. For a Day 5 (blastocyst) transfer, add 261 days. For a Day 3 transfer, add 263 days. This is equivalent to 40 weeks from the theoretical last menstrual period.
Is the IVF due date more accurate than natural conception?
Yes. IVF due dates tend to be more accurate because the exact date of fertilization and embryo age are known precisely, unlike natural conception where ovulation date is estimated.
What is the difference between Day 3 and Day 5 embryo transfers?
Day 3 embryos (cleavage stage) have about 6-8 cells. Day 5 embryos (blastocysts) are more developed with about 70-100 cells. Day 5 transfers generally have higher success rates.
What trimester milestones should I expect?
First trimester (weeks 1-12): major organ development, morning sickness common. Second trimester (weeks 13-27): anatomy scan around week 20, baby movements felt. Third trimester (weeks 28-40): rapid growth, delivery preparation.