How this IVF week by week pregnancy calculator works
This IVF calculator estimates your gestational age, due date, and a practical week-by-week timeline using your embryo transfer date. It is useful for both fresh IVF cycles and frozen embryo transfer (FET) pregnancies.
In natural conception, pregnancy dating starts from the last menstrual period (LMP). IVF is different because fertilization timing is known. So we use a medical conversion to map IVF dates to standard obstetric weeks.
IVF dating formula (simple and accurate)
- Step 1: Start with your embryo transfer date.
- Step 2: Subtract 14 days + embryo age to estimate the LMP-equivalent date.
- Step 3: Add 280 days to estimate a 40-week due date.
| Transfer Type | Gestational Age on Transfer Day | Due Date Shortcut |
|---|---|---|
| Day 3 transfer | 2 weeks + 3 days | Transfer date + 263 days |
| Day 5 transfer | 2 weeks + 5 days | Transfer date + 261 days |
| Day 6 transfer | 2 weeks + 6 days | Transfer date + 260 days |
How to use this IVF pregnancy calculator
- Enter your embryo transfer date.
- Select embryo age (Day 3, Day 5, or Day 6).
- Choose the date you want to calculate for (defaults to today).
- Click Calculate IVF Pregnancy Week.
You’ll instantly see your estimated due date, current week and day of pregnancy, trimester, milestone dates, and a full 1–40 week schedule.
IVF week-by-week pregnancy overview
First trimester (weeks 1–13)
- Weeks 4–5: hCG rises; many patients begin beta monitoring.
- Weeks 6–7: early ultrasound may confirm sac, yolk sac, and heartbeat.
- Weeks 8–10: rapid embryo growth; nausea and fatigue often peak.
- Weeks 11–13: transition to end of first trimester and optional screening.
Second trimester (weeks 14–27)
- Energy often improves and symptoms may ease.
- Week 20 anatomy scan checks detailed fetal development.
- Weeks 24–28 include glucose testing and ongoing growth checks.
Third trimester (weeks 28–40)
- Steady fetal weight gain and increased prenatal monitoring.
- Weeks 35–37 include late-pregnancy planning and delivery prep.
- Week 40 is your estimated due date, though labor timing can vary.
Common IVF dating questions
Is IVF due date calculation more accurate?
Usually yes. Because embryo age and transfer timing are known, IVF pregnancies have a precise conception timeline.
Does this work for frozen embryo transfer (FET)?
Yes. The dating method is the same for fresh and frozen embryo transfer as long as transfer date and embryo age are correct.
Can this replace my clinic’s instructions?
No. This calculator is educational. Your fertility specialist or OB should always guide final dating, scans, and treatment decisions.