IVF & Frozen Embryo Transfer Due Date Calculator

How to use it

• Check your embryology or discharge summary for the transfer date and the embryo day — it will say day 3, day 5 or day 6.
• Select that option and enter the transfer date. For a frozen transfer, use the date of the transfer itself, not the date the embryos were originally created.
• If you only have the egg-retrieval date, pick that option instead — it is treated as the day of ovulation.

How the maths works

• Pregnancy is dated from a notional last menstrual period, two weeks before ovulation. For IVF we work backwards from the known embryo age.
• Day-3 transfer: due date = transfer date + 263 days. Day-5 blastocyst: + 261 days. Day-6 blastocyst: + 260 days. Egg retrieval or IUI: + 266 days.
• Frozen and fresh transfers use the same rule — what matters is the age of the embryo on the day it was put back, not how long it was frozen.
• Twins from a double transfer are usually delivered earlier than the calculated date; your obstetrician will plan around 36–38 weeks depending on the type of twins.

Your first weeks after transfer

Continue every medicine exactly as prescribed until your doctor stops it — luteal support is not optional in an IVF pregnancy. Attend your beta-hCG blood tests on the dates given, and your first viability scan at around 6–7 weeks. Call the hospital straight away for heavy bleeding, severe one-sided pain, breathlessness, or rapid abdominal swelling after retrieval.