Frequently Asked Questions

It adds 266 days minus embryo age to the clinic date you enter. A Day 5 blastocyst uses +261 from transfer. A Day 3 embryo uses +263. Retrieval or IUI usually uses +266. Frozen time in the tank is not added.

Obstetric charts include two notional weeks before fertilization so IVF pregnancies line up with a 40-week calendar. The embryo’s documented age is already on the chart the morning it is placed.

Day 3 is two days younger, so the due date is two days later than a Day 5 transfer on the same calendar date. Mixing the labels shifts paperwork and ultrasound comparisons.

Use those lines: Day 6 = +260, Day 7 = +259. Do not round to Day 5 because a forum did. Open “More options” on the calculator if those choices are hidden.

No. Enter the day the embryo was transferred into the uterus. Freeze date, first estrogen pill, and last retrieval do not belong in the date box.

Yes — choose donor/IUI and enter the insemination date. Fertilization may not occur at that exact hour, so IUI dating is looser than a known blastocyst transfer. Do not use trigger-shot night unless that is how your clinic dated you.

Use retrieval / fertilization (+266) until a transfer with a documented embryo day exists. After transfer, switch to Day 3/5/6/7. Do not keep adding retrieval math on top of a completed transfer.

Only if you intentionally pick last menstrual period. Medicated FET patients often never had a usable LMP. Period apps are why this site exists.

Many teams keep the transfer-based date if a first-trimester scan is within about five days. Later scans are worse at dating. A large gap is a clinic conversation. See IVF due date vs ultrasound.

No. Serial betas speak to whether hCG is rising. They do not change embryo age at transfer. Use the beta panel to compare two draws; keep dating from the transfer (or retrieval) date.

On transfer morning, 2 weeks 5 days. Then add calendar days. The weeks-pregnant mode on the same calculator shows gestational age today.

Most apps start from LMP or a default “4 weeks at positive test.” IVF already knows embryo age. Delete or ignore LMP widgets once you have a transfer date. More: why pregnancy apps get IVF dates wrong.

Dating still uses embryo stage at transfer, not the number of sacs. Twins usually share one EDD; delivery timing is a separate obstetric plan.

No. Copy the summary and take it to the team that owns the chart. About 4–5% of babies arrive on the exact calendar day.

No. The calculator runs in your browser. See Privacy.

No. They are starting questions on /calculator/. Old URLs redirect here so Google does not see six copies of the same widget.

Guides are written and edited by Dr. Farhan. They are educational explainers, not a personal consult. We do not put a hospital-style “medically reviewed” badge on every paragraph. Offsets are checked against public ART counting and documents such as ACOG Committee Opinion 700. Follow your clinic when they disagree.

Dr. Farhan, editor. Read the editorial policy.

No. If Google AdSense is showing, ads never edit Day 3/Day 5 offsets. Cookie choices are in the footer.

Yes. The free IVF Due Date Calculator on Google Play uses the same transfer-based math. Confirm everything with your clinic.

The IVF pregnancy guide covers early pregnancy, scans, and when to call. Articles live at /articles/.

Email [email protected] with the URL, embryo day, and date you entered. Do not attach unredacted lab PDFs. Contact page.