Pregnancy due date calculator - Dr Dimitrios Mavrelos

Pregnancy due date & gestational age (after embryo transfer)

For a pregnancy conceived through IVF, dating is anchored to the embryo transfer rather than a last menstrual period. Enter the transfer date and embryo stage to get the estimated due date and current gestational age.

Inputs

Embryo transfer date Embryo stage at transfer Show gestational age on

Defaults to today. Change to see gestation at any date (e.g. a scan date).

Results

Estimated due date (40 weeks)

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Gestational age on chosen date

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Equivalent LMP date

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Conception (fertilisation) date

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Milestone	Gestational age	Date

Methods

Gestational age is conventionally counted from 2 weeks before conception (the notional last menstrual period). A transferred embryo is already (embryo day) days past fertilisation, so at transfer the gestational age is 14 + embryo day days — for a Day-5 blastocyst, 2 weeks 5 days. The estimated due date is transfer date + (266 − embryo day) days (261 days for a Day-5 blastocyst), equivalent to 266 days from fertilisation / 280 days from the notional LMP.

Disclaimer

This calculator gives standard IVF dating estimates for guidance only. The estimated due date is a statistical average; most births occur in the weeks around it. Dating may be revised by an early ultrasound scan. Always follow the advice of your clinician and your maternity team.