IVF Due Date Calculator
Model gestational progression schedules. Calculates pregnancy EDD based on transfer timing configurations (Day 3/5/6 blastocysts).
Transfer Parameters
Embryo Stage
Awaiting Transfer Parameters
Enter the date of embryo transfer and configure cell age stages to draw diagnostic schedules.
Calculations: Why IVF Gestational Timing Differs
Equivalent Last Menstrual Period (LMP)
In standard pregnancies, doctors calculate gestational age based on the first day of the last period. However, ovulation timing varies from cycle to cycle. In IVF, because the exact day of fertilization (egg retrieval or thaw fertilization) is known with absolute certainty, the "equivalent LMP" is calculated mathematically:
- For Day 3 embryos: Equivalent LMP is 17 days prior to transfer.
- For Day 5 embryos: Equivalent LMP is 19 days prior to transfer.
- For Day 6 embryos: Equivalent LMP is 20 days prior to transfer.
This standardizes gestational parameters, ensuring scans (NT, anatomy) are scheduled precisely when anatomical structures are visible.
Critical Milestones Explained
- Beta-hCG test: Scheduled 9-11 days after a blastocyst transfer. Testing too early can yield false negatives (if hormone concentrations are too low) or false positives (from trigger injection residues).
- Cardiac Scan: Scheduled at 6-7 weeks gestational age to check cardiac activity. Seeing heart activity at this point correlates with a 90%+ probability of pregnancy continuation.