IVF Due Date & Scan Dates
Frozen transfer? Natural-conception due math? This computes the clinic's dating arithmetic, due date to the day, plus every standard scan date.
Clinic dating convention: on transfer day you are pregnant 14 days + embryo age, a day-5 transfer lands at exactly 19 weeks + 0 days gestational age. Frozen vs fresh doesn't change dating; the embryo age does. We add due date = LMP-equivalent + 280 days.
How the math works
Obstetric dating counts from the LMP-equivalent, 2 weeks before conception:
- LMP-equivalent = transfer date − (14 + embryo age) days. Day-5 transfer: −19 d; day-3: −17 d. For natural conception: ovulation date − 14 d (
−7mode treats input as ovulation, LMP-equ = ovulation − 14 = ovulation+… convention: we use LMP-eq = ovulation − 14). - Due date = LMP-equivalent + 280 days (= transfer + 261 d for day-5, +263 for day-3, the "due dates 2 weeks apart" for same-day transfers at different embryo ages is real and normal).
- Gestational age today = (today − LMP-eq) in weeks+days. Trimesters: 1st <14 wks, 2nd 14–27, 3rd ≥28.
- Standard IVF schedule: beta hCG 9–14 d post-transfer; first ultrasound ~6 wks gestational (6.5–7); NT/dating scan 11 wks 0 d – 13 wks 6 d; anatomy 18–22 wks (standard 20). Dates shown are the schedule center; clinics shift ±a few days.
Frequently asked
How is a due date calculated after IVF transfer?
Transfer date + 266 days for a day-5 blastocyst (263 for day-3), which equals LMP-equivalent + 280. Frozen transfers use the embryo's age at freezing, not the thaw date.
How many weeks pregnant am I after a transfer?
On transfer day you're 19 weeks 0 days with a day-5 blastocyst, 17 weeks 0 days with a day-3 embryo, clinics count this way, not from conception.
When is the beta test after transfer?
Day-5 transfers: beta 9–11 days post-transfer (clinics standardize ~day 9–11); day-3 transfers: 12–14 days. The tool prints your clinic-standard date.