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FET Due Date Calculator – Frozen Embryo Transfer

Calculate your pregnancy due date after FET

This calculator provides estimates only. Pregnancy due dates should be confirmed with your healthcare provider through ultrasound and medical evaluation.
Calculate Due Date

How to Use

  1. Enter your embryo transfer date
  2. Select your embryo development day (day 3 or day 5)
  3. Click calculate to see your estimated due date
  4. Review your current pregnancy week and conception date

What is FET?

Frozen Embryo Transfer (FET) is an assisted reproductive technology procedure where embryos that have been frozen from a previous IVF cycle are thawed and transferred to the uterus. FET allows couples to use embryos from a previous cycle without undergoing another egg retrieval.

The due date calculation for FET pregnancies is slightly different from natural conception because we know the exact date of conception relative to the transfer date.

How FET Due Date Calculation Works

The calculation accounts for the embryo's development stage at transfer:

  • Day 3 embryo: The transfer date is considered 17 days after conception (14 days + 3 days)
  • Day 5 embryo (blastocyst): The transfer date is 19 days after conception (14 days + 5 days)
  • The due date is calculated as 266 days from the calculated conception date
  • This equals 280 days from the last menstrual period equivalent

Embryo Development Stages

  • Day 3 embryo: Typically 6-8 cells, called a cleavage-stage embryo
  • Day 5 embryo: Called a blastocyst, contains about 70-100 cells
  • Day 6 embryo: Also a blastocyst, sometimes used if day 5 embryos aren't ready
  • Blastocyst transfers (day 5/6) generally have higher success rates
  • The embryo day affects how the due date is calculated

Pregnancy After FET

  • Early ultrasounds will confirm the due date and pregnancy viability
  • Your healthcare provider may adjust the due date based on ultrasound measurements
  • Pregnancies from FET are monitored similarly to natural pregnancies
  • Continue any prescribed medications as directed by your doctor
  • Attend all scheduled prenatal appointments
  • Most FET pregnancies proceed normally and result in healthy babies

Frequently Asked Questions

Is the FET due date accurate?
The FET due date is generally very accurate because the conception date can be precisely determined from the transfer date and embryo day. However, your healthcare provider may adjust it based on early ultrasound measurements.
Does embryo day (3 vs 5) affect pregnancy outcomes?
Day 5 blastocyst transfers typically have higher success rates per transfer compared to day 3 embryos. However, both can result in healthy pregnancies. The embryo day does affect how the due date is calculated.
When will I have my first ultrasound after FET?
Most fertility clinics schedule the first ultrasound around 6-7 weeks of pregnancy (about 2-3 weeks after a positive pregnancy test). This confirms pregnancy viability and the number of embryos implanted.
Can my due date change after calculation?
Your healthcare provider may adjust your due date based on early ultrasound measurements, typically performed between 8-13 weeks of pregnancy. However, FET due dates are usually very accurate and rarely change significantly.

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