What gestational age am I at after a Day 5 blastocyst transfer?

At the moment of a Day 5 blastocyst transfer you are 19 days gestational age, which equals 2 weeks and 5 days. This is because gestational age counts from the equivalent of day 1 of the last menstrual period, which by convention is 14 days before fertilization (egg retrieval). Add 14 days plus the 5-day embryo age to get 19 gestational days. After the transfer, gestational age increases by 1 day per calendar day.

When is my first pregnancy ultrasound after IVF?

Most IVF clinics schedule a viability scan between 6 and 8 gestational weeks, approximately 4 to 6 weeks after a Day 5 embryo transfer. This scan confirms a heartbeat, rules out ectopic pregnancy, and verifies the number of implanted embryos. Your clinic will book this automatically after a positive beta hCG blood test. The 8 to 12 week nuchal translucency scan follows, then the anatomy scan at weeks 18 to 20.

Does a Day 5 vs Day 6 blastocyst transfer change the due date?

Yes, by one day. A Day 6 blastocyst transfer produces an EDD one day later than a Day 5 transfer from the same egg retrieval. EDD for Day 5 transfer = transfer date plus 261 days. EDD for Day 6 transfer = transfer date plus 260 days. From the same retrieval date, both approaches yield the same EDD (retrieval date plus 266). The one-day difference in transfer date is exactly offset by the one-day difference in the addition.

How do I calculate gestational age from my IVF egg retrieval date?

Add 14 days to the number of days since egg retrieval. By convention, gestational age begins 14 days before fertilization (the equivalent of the last menstrual period day in natural cycles). So on the day of egg retrieval you are 14 gestational days old. Each day after retrieval adds one gestational day. For example, 30 days after retrieval you are 44 gestational days, or 6 weeks and 2 days gestational age.

IVF Due Date Calculator

Q: Can I use this calculator for a frozen embryo transfer?

Yes. For a frozen embryo transfer (FET), enter your transfer date and the embryo stage at the time the embryo was frozen, typically Day 5 or Day 6. The formula is the same as for fresh transfers because the freezing and thawing process does not add to the embryo's biological age. Day 5 FET: add 261 days to transfer date. Day 6 FET: add 260 days to transfer date.

Q: Can I use this calculator for donor egg IVF?

Yes. The due date formula uses the embryo's age at transfer, not whose eggs were used. Enter the embryo transfer date and the embryo stage exactly as you would for a standard IVF cycle. For gestational age purposes, the donor's egg retrieval date is still used as the fertilization reference point, which is already built into the embryo stage entered at transfer.

Enter your embryo transfer date and embryo stage, or your egg retrieval date, to find your IVF estimated due date, current gestational age, and milestone timeline.

Embryo Transfer Date

Embryo Stage at Transfer

Egg Retrieval Date

Estimated Due Date

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Gestational Age

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Trimester

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Countdown

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Key Milestones

Milestone	Date	Status

🧬 What is an IVF Due Date Calculator?

An IVF due date calculator estimates your estimated due date (EDD) using the precise fertilization date known from your IVF records, rather than the last menstrual period (LMP) used in natural pregnancy dating. In standard obstetric dating, doctors add 280 days (40 weeks) to the LMP and assume ovulation occurs on day 14 of a 28-day cycle. In IVF, egg retrieval day is the documented fertilization date, so the calculation is more direct and more accurate.

This tool is used by women who have undergone in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), or frozen embryo transfer (FET) to find their EDD without waiting for a clinic appointment. By entering your embryo transfer date and embryo stage (Day 3, Day 5, or Day 6), or your egg retrieval date, you instantly receive your due date, current gestational age in weeks and days, trimester, and a timeline of key pregnancy milestones including the anatomy scan, viability at week 24, full term at week 39, and your due date at week 40.

The key distinction between IVF and natural dating is precision. Because the fertilization date is documented in the laboratory, IVF due dates carry a margin of error of only 2 to 3 days, compared to 7 or more days for LMP-based estimates in women with irregular cycles. This is why IVF-dated pregnancies are rarely re-dated at the first-trimester ultrasound, whereas naturally conceived pregnancies are revised approximately 20 to 30 percent of the time. The 266-day period from fertilization to birth (38 weeks of fetal age) is biologically the same whether conception was natural or assisted.

The gestational age convention adds 14 days to the embryo's fetal age, mirroring the assumed LMP-to-ovulation gap in a natural 28-day cycle. This means that at a Day 5 blastocyst transfer, you are already 19 gestational days (2 weeks and 5 days) into your pregnancy by standard obstetric counting. This calculator applies this convention automatically so that your gestational age matches what your fertility clinic and obstetrician will use.

📐 Formula

EDD = Transfer Date + (266 − Embryo Day)

EDD = Estimated Due Date

Transfer Date = calendar date of embryo transfer

Embryo Day = embryo age at transfer in days (3, 5, or 6)

266 = days from fertilization (egg retrieval) to birth (38 weeks)

Example: Day 5 transfer on May 5, 2026 → EDD = May 5 + 261 = January 21, 2027

EDD = Egg Retrieval Date + 266 days

Egg Retrieval Date = day eggs were collected (fertilization day, Day 0)

266 = days from fertilization to birth (used when embryo age is 0)

Example: Retrieval on May 8, 2026 → EDD = May 8 + 266 = January 29, 2027

📖 How to Use the IVF Due Date Calculator

Steps

Choose your input method - Select By Transfer Date if you know when your embryo was transferred, or By Egg Retrieval to enter your retrieval date directly.

Enter your date - For transfer mode, pick the embryo transfer date and select the embryo stage from the dropdown (Day 3 cleavage, Day 5 blastocyst, or Day 6 blastocyst). For retrieval mode, enter the date your eggs were collected.

Click Calculate - Your estimated due date, current gestational age, trimester, and a six-milestone timeline appear instantly. Dates update automatically each day you revisit the page.

💡 Example Calculations

Example 1 - Day 5 Blastocyst Transfer

Day 5 blastocyst transferred on May 5, 2026

Embryo stage = Day 5. Days to add = 266 minus 5 = 261.

EDD = May 5, 2026 + 261 days = January 21, 2027.

Gestational age at transfer = 14 + 5 = 19 days (2 weeks 5 days). As of June 1, 2026 (27 days later): GA = 19 + 27 = 46 days = 6 weeks 4 days.

EDD = January 21, 2027 | Gestational Age on June 1 = 6w4d

Try this example →

Example 2 - Day 3 Cleavage Stage Transfer

Day 3 embryo transferred on April 20, 2026

Embryo stage = Day 3. Days to add = 266 minus 3 = 263.

EDD = April 20, 2026 + 263 days = January 8, 2027.

Gestational age at transfer = 14 + 3 = 17 days (2 weeks 3 days). As of June 1, 2026 (42 days later): GA = 17 + 42 = 59 days = 8 weeks 3 days.

EDD = January 8, 2027 | Gestational Age on June 1 = 8w3d

Try this example →

Example 3 - Egg Retrieval Date Mode

Egg retrieval performed on May 8, 2026

Retrieval date = May 8, 2026. This is fertilization day (Day 0).

EDD = May 8, 2026 + 266 days = January 29, 2027.

Gestational age at retrieval = 14 days. As of June 1, 2026 (24 days later): GA = 14 + 24 = 38 days = 5 weeks 3 days.

EDD = January 29, 2027 | Gestational Age on June 1 = 5w3d

Try this example →

❓ Frequently Asked Questions

How is an IVF due date calculated from a Day 5 blastocyst transfer?+

Add 261 days to your Day 5 embryo transfer date. The formula is EDD = Transfer Date + (266 minus embryo age). A Day 5 blastocyst is 5 days old at transfer, so you subtract 5 from the 266-day fertilization-to-birth period. This yields the same result as adding 266 days to the egg retrieval date, because the embryo spent 5 days in the lab between retrieval and transfer.

How is an IVF due date calculated from a Day 3 embryo transfer?+

Add 263 days to your Day 3 transfer date. A Day 3 embryo (cleavage stage) is 3 days post-fertilization at the time of transfer, so EDD = Transfer Date + (266 minus 3) = Transfer Date + 263. Because Day 3 embryos are transferred earlier in development than Day 5 blastocysts, a Day 3 transfer from the same retrieval produces an EDD 2 days earlier than a Day 5 transfer.

Is an IVF due date more accurate than a natural pregnancy due date?+

Yes. IVF dating is based on the known fertilization date (egg retrieval), giving an accuracy of plus or minus 2 to 3 days. Natural LMP-based dating assumes ovulation on day 14, which is incorrect for women with irregular cycles, producing a margin of plus or minus 7 or more days. IVF due dates are rarely revised by the first-trimester ultrasound, whereas LMP-based dates are revised in roughly 20 to 30 percent of pregnancies.

What gestational age am I at a Day 5 blastocyst transfer?+

At the moment of a Day 5 transfer you are 19 gestational days, which equals 2 weeks and 5 days. Gestational age adds 14 days to fetal age by convention, mirroring the LMP-to-ovulation gap in natural cycles. So at transfer: 14 days (convention) plus 5 days (embryo age) equals 19 gestational days. After transfer, gestational age increases by 1 day per calendar day.

Can I use this calculator for a frozen embryo transfer (FET)?+

Yes. For a frozen embryo transfer, enter your transfer date and the embryo stage at the time the embryo was frozen, typically Day 5 or Day 6. The calculation is identical to a fresh transfer. Freezing and thawing does not add to the embryo's biological age, so the same formula applies: EDD = FET date + (266 minus embryo day at freeze).

Can I use this calculator for donor egg IVF?+

Yes. The due date formula depends on the embryo age at transfer, not the source of the eggs. Enter the transfer date and embryo stage as you would for a standard IVF cycle. The donor's egg retrieval date is the biological fertilization reference point, and that is already encoded in the embryo stage you enter at transfer. Results are identical whether eggs were yours or a donor's.

Why might my IVF due date differ from what my LMP would predict?+

LMP-based dating assumes ovulation at day 14 of a 28-day cycle, but IVF ovarian stimulation shifts egg retrieval to a point that rarely aligns with a natural day-14 ovulation. Women with cycles longer or shorter than 28 days would get an incorrect LMP-based date. IVF dating bypasses this entirely by anchoring the calculation to the documented egg retrieval date, which is why the two dates often differ by a week or more.

When is my first pregnancy ultrasound after an IVF transfer?+

Most IVF clinics schedule a viability scan between 6 and 8 gestational weeks, roughly 4 to 6 weeks after a Day 5 transfer. This scan confirms a heartbeat and rules out ectopic pregnancy. After a positive beta hCG, your clinic books the scan automatically. The nuchal translucency scan follows at 11 to 13 weeks, and the anatomy scan is at 18 to 20 gestational weeks.

Does a Day 5 versus Day 6 blastocyst transfer change the due date?+

Yes, by one day. A Day 6 blastocyst transfer EDD = transfer date plus 260 days. A Day 5 transfer EDD = transfer date plus 261 days. If both came from the same egg retrieval batch, the due dates are identical (retrieval date plus 266), because the one-day difference in transfer date is exactly offset by the one fewer day added. The difference only appears when comparing transfers on the same calendar date.

How do I calculate gestational age from my egg retrieval date?+

Add 14 to the number of days since retrieval. By convention, gestational age begins 14 days before fertilization (the LMP equivalent). On the retrieval day you are 14 gestational days old. Each subsequent day adds one day. For example: 30 days after retrieval you are 44 gestational days, or 6 weeks and 2 days. This matches the gestational age shown in your clinic records and on all ultrasound reports.

What is the EDD formula for an embryo transferred at a day other than 3, 5, or 6?+

Use the general formula: EDD = Transfer Date + (266 minus embryo age in days). Day 2 transfer (uncommon): add 264 days. Day 4 morula (rare): add 262 days. Day 7 extended culture (very rare): add 259 days. In all cases, the embryo age is the number of days from egg retrieval to the actual transfer date, subtracted from 266.

How accurate is this IVF due date calculator for planning prenatal appointments?+

Very accurate for scheduling. Because IVF uses a known fertilization date, the EDD is reliable to within 2 to 3 days. All standard appointments (beta hCG at 9 to 11 days post-transfer, viability scan at 6 to 8 weeks, nuchal scan at 11 to 13 weeks, anatomy scan at 18 to 20 weeks) can be planned from the due date shown here. Your fertility clinic or obstetrician provides the actual appointment bookings and interprets scan findings.

🔗 Related Calculators

📌 Quick Tips

💡A Day 5 blastocyst transfer gives an EDD that is 2 days later than a Day 3 transfer from the same egg retrieval, because the embryo spent 2 extra days in the lab before being transferred.

💡IVF gestational age adds 14 days to the fetal age, just like natural pregnancy. At a Day 5 transfer your gestational age is 2 weeks and 5 days (19 days), not 5 days.

💡For frozen embryo transfers (FET), use the same formula as fresh transfers. The embryo stage at the time of freezing (typically Day 5 or 6) is the number to enter, not the days since thawing.

💡If your clinic changes your due date at the 8-12 week ultrasound, the scan measurement takes priority. An early ultrasound accurate to plus or minus 5 days is considered more reliable than the transfer-date formula.

💡The anatomy scan is typically scheduled between weeks 18 and 20. Your OB or MFM will book this approximately 3 to 4 months after your positive beta hCG result, based on the transfer-based gestational age.