Women's Health · Guide
IVF and Frozen Embryo Transfer Due Date
With IVF you know the embryo's exact age, so the due date is one of the most precise in pregnancy.
Want the answer for your own numbers? Use the free Pregnancy Due Date Calculator — it does every step below for you.
The formula
A natural due date is 266 days after conception. With IVF, the embryo is already a few days old when it is transferred. So you subtract the embryo's age from 266.
| Embryo at transfer | Add to transfer date | You are this far along on transfer day |
|---|---|---|
| Day 3 embryo | 263 days | 2 weeks 3 days |
| Day 5 blastocyst | 261 days | 2 weeks 5 days |
| Day 6 blastocyst | 260 days | 2 weeks 6 days |
The same numbers work for a fresh transfer and a frozen embryo transfer (FET). Freezing pauses the embryo's development, so only its age at transfer counts — not how long it was frozen.
Worked example
Day 5 FET on 10 March 2026
10 March 2026 + 261 days.
Due date: 26 November 2026
Had it been a day 3 embryo, the due date would be 28 November. A day 6 blastocyst would give 25 November.
Why your clinic says you are "already pregnant" for two weeks
Pregnancy weeks are counted as if from a last period, two weeks before conception. That is how all pregnancy charts and scans work. So on the day of a day 5 transfer, you are counted as 2 weeks 5 days pregnant. Your clinic may give you an "equivalent last period" date: the transfer date minus 19 days for a day 5 embryo, or minus 17 days for a day 3 embryo.
Key dates after a transfer
- Blood test (beta hCG): usually about 9 to 11 days after a day 5 transfer — your clinic will set the exact day.
- First scan: often around 6 to 7 weeks of pregnancy, about 3 to 4 weeks after transfer.
- End of the first trimester: 13 weeks 6 days.
Your pregnancy timeline after a day 5 transfer
Using the same example — a day 5 blastocyst transferred on 10 March 2026, with an equivalent last period of 19 February:
| Milestone | Pregnancy week | Date |
|---|---|---|
| Transfer day | 2 weeks 5 days | 10 March 2026 |
| Around the blood test | 4 weeks | 19 March 2026 |
| Typical first scan | 6–7 weeks | 2–9 April 2026 |
| End of first trimester | 13 weeks 6 days | 27 May 2026 |
| Anatomy scan (approx.) | 20 weeks | 9 July 2026 |
| Third trimester begins | 28 weeks | 3 September 2026 |
| Early term begins | 37 weeks | 5 November 2026 |
| Full term begins | 39 weeks | 19 November 2026 |
| Due date | 40 weeks | 26 November 2026 |
| Late term | 41 weeks | 3 December 2026 |
Your own clinic and maternity team set the exact dates for tests and scans.
Twins after IVF
Twins have the same due date formula, but twin pregnancies are usually delivered earlier. Many are born around 36 to 37 weeks. Your care team will plan timing with you.
Will a scan change my IVF due date?
Usually not. Because the transfer date is known exactly, most clinics keep the IVF date even if an early scan measures a few days off. That is different from natural pregnancies, where an early scan often resets the date.
Enter your transfer date and embryo age in the due date calculator to get your own date and current week.
Other fertility treatments
- Donor egg or donor embryo IVF — the same formula. Only the embryo’s age at transfer counts, not the age of the egg or how long it was stored.
- IUI or timed intercourse — there is no embryo age to use. The due date is worked out from the last period or the known ovulation date, like a natural pregnancy: ovulation date + 266 days.
- Fresh vs frozen transfer — identical maths. Freezing pauses development, so a day 5 embryo is still treated as day 5.
Frequently asked questions
Add 261 days to the transfer date for a day 5 blastocyst, 263 days for a day 3 embryo, or 260 days for a day 6 blastocyst. A day 5 FET on 10 March 2026 gives a due date of 26 November 2026.
For a day 5 transfer you are counted as 2 weeks 5 days pregnant on the day itself. For a day 3 transfer you are 2 weeks 3 days. Pregnancy weeks always include two weeks before conception.
No. Freezing pauses development, so only the embryo’s age when it was frozen and transferred matters. A day 5 blastocyst frozen for two years still gives a due date 261 days after transfer.
Add 260 days to the transfer date. A day 6 transfer on 10 March 2026 gives a due date of 25 November 2026, one day earlier than a day 5 embryo transferred on the same day.
Sources and further reading
- ACOG — Methods for estimating the due date — including pregnancies from assisted reproduction
- ACOG — Methods for Estimating the Due Date — how due dates are set for IVF pregnancies using embryo age and transfer date