Pregnancy Dating for IVF
Embryo transfer data offer precise dating. Input your transfer details to determine gestational age, due date, and milestone appointments.
Type does not change EDD math but may influence medication schedules.
Leave blank to calculate gestational age today.
How to Use This Calculator
Enter official transfer information
Use the date and embryo age provided by your IVF clinic. Fresh and frozen transfers use the same dating formula.
Adjust the “as of” date if needed
By default, gestational age is calculated as of today, but you can choose any reference date.
Review milestone appointments
The calculator provides estimated timing for early heartbeat ultrasound, first trimester screening, and anatomy scan.
Formula
Equivalent LMP = Transfer date − (Embryo age − 3) − 14 days
Estimated due date = Transfer date + 266 − (Embryo age − 3)
Gestational age (days) = As-of date − Equivalent LMP
Gestational age (weeks/days) = GA days converted to weeks + remainder days
Full Description
IVF dating relies on precise knowledge of embryo development. Embryos transferred at the blastocyst stage (day 5–6) are biologically further along than cleavage-stage embryos (day 3), so equivalent LMP and due date calculations adjust accordingly. Obstetric care typically uses the IVF-provided due date for prenatal scheduling, ensuring consistent tracking throughout pregnancy.
Frequently Asked Questions
Do I still need an ultrasound for dating?
Ultrasound confirms implantation and viability, but the IVF due date remains the reference unless discrepancies emerge.
What if multiple embryos were transferred?
Dating is identical. Ultrasounds will determine the number of gestational sacs and embryos progressing.
Does frozen transfer change timing?
No. Frozen transfers are scheduled relative to the endometrium to mimic natural timing. Use the transfer date and embryo age regardless of fresh/frozen.
Can the due date change later?
Rarely. If later ultrasounds show significant deviation, the care team may reassess, but IVF dates are usually definitive.