How is a due date calculated after a frozen embryo transfer?

Exactly as for a fresh transfer: transfer date plus 266 days, minus the embryo's age when it was frozen. For the most common case, a day-5 blastocyst, that is the transfer date plus 261 days.

Does the freeze date or the original retrieval date matter?

No. Development stops while the embryo is frozen and resumes on thaw, so only the embryo's age at freezing and the date it was transferred are used. An embryo frozen three years ago is dated the same as one frozen last month.

My FET was a day-6 blastocyst — what changes?

Subtract six days instead of five: the due date becomes the transfer date plus 260 days, and you are 2 weeks and 6 days pregnant on transfer day.

Is a medicated FET dated differently from a natural FET?

No. The protocol changes how your lining is prepared and when the transfer is scheduled, but once the transfer happens the dating is identical.

Why does my clinic's FET due date differ by a day?

Some clinics date from the notional ovulation or progesterone start rather than the transfer itself, which can shift the date by a day. A one-day difference has no practical effect on your care.

FET Due Date Calculator

Enter your frozen embryo transfer date for your estimated due date. This page assumes a day-5 blastocyst, the most common frozen embryo — use the day-3 or day-6 pages if yours was frozen at a different stage.

Embryo transfer date

Estimated due date

Tuesday, June 15, 2027

Transfer date + 261 days. On transfer day you are counted as 2w 5d pregnant. Frozen and fresh transfers of the same embryo age give the same due date.

This is an estimate for information only — only about 1 in 20 babies arrive on their due date. Always confirm dates with your midwife or doctor.

What happens after a day-5 transfer

Typical timings for a transfer on Sunday, September 27, 2026. Your clinic's own schedule always takes priority.

Milestone	Day past transfer	Gestational age	Date
Transfer day	—	2w 5d	Sunday, September 27, 2026
Earliest reliable home test	9dp5dt	4w 0d	Tuesday, October 6, 2026
First beta hCG (typical)	10dp5dt	4w 1d	Wednesday, October 7, 2026
Second beta hCG (typical)	12dp5dt	4w 3d	Friday, October 9, 2026
First ultrasound (typical)	21dp5dt	5w 5d	Sunday, October 18, 2026

Why freezing does not change the date

Vitrification halts development completely. A blastocyst frozen on day 5 is still, biologically, a day-5 blastocyst when it is thawed, whether that happens a month or five years later.

So the calculation only ever needs two inputs: the age the embryo had reached when it was frozen, and the date it was placed in the uterus. Retrieval date, freeze date and storage time all drop out.

Medicated, natural and modified natural FET

A medicated FET uses oestrogen and progesterone to build and time the lining. A natural FET tracks your own ovulation and transfers a set number of days after it. A modified natural cycle adds a trigger shot to pin the timing down.

These protocols change the run-up to transfer, not the dating afterwards. If you are still planning the cycle rather than counting from a completed transfer, the FET cycle calculator maps the whole sequence from cycle start to beta.

What FET dating means for your scan schedule

The first ultrasound is usually booked at around 6 to 7 weeks of gestation, which is roughly three weeks after a day-5 FET. At that scan the clinic looks for a gestational sac, a yolk sac and, close to 7 weeks, a heartbeat.

Most clinics then discharge you to routine maternity care between 8 and 10 weeks, keeping the IVF due date unless a scan disagrees substantially.

If you had PGT-tested embryos

Genetic testing requires a biopsy at blastocyst stage, so tested embryos are almost always day-5 or day-6 and are frozen while results come back. Use the stage recorded on your embryology report.

The testing itself has no effect on dating — it only affects which embryo was chosen for transfer.

Other transfer days

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