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Cleavage rate calculator

Are my embryos growing on day 2 and 3?

Q: Is day 3 a good time to judge quality?

Only partly. Most embryos cleave; the informative attrition happens between day 3 and day 5. A good cleavage rate does not guarantee blastocysts.

Q: Should we transfer on day 3?

If very few embryos are available, some units transfer earlier rather than risk none surviving to day 5. It is a genuine clinical judgement — ask what your unit would do and why.

Q: My embryos cleaved but none reached blastocyst. Why?

Embryonic genome activation happens around day 3 — before that the embryo runs largely on maternal machinery. Arrest between day 3 and day 5 is where intrinsic embryo problems typically show, which is why the drop-off happens there and not earlier.

How many fertilised embryos progressed through the cleavage stage by day 3.

Cleaved embryos

Dividing normally on day 3

Normally fertilised (2PN)

Fertilised on day 1

These are example numbers. Replace them with yours, then press Calculate.

Example answer

86%

85%+

Most fertilised embryos progressing normally, which is what is typically expected at this stage.

This is a guide, not a diagnosis. Share the result with your doctor.

Your result on the scale

The ranges this calculator uses. Yours is highlighted.

Your numbers

Everything worked out from what you entered.

Cleaved embryos: 6
Normally fertilised (2PN): 7

What each result means

Your result is highlighted. Your own clinic's advice always comes first.

Your result<70%

Low. Early arrest points toward egg or sperm quality rather than laboratory conditions in most cases.

Your result70–85%

Within the usual range, though at the lower end.

Your result85%+

Most fertilised embryos progressing normally, which is what is typically expected at this stage.

Where this fits in your journey

The usual order, from trying to conceive to pregnancy. Not everyone needs every stage. This calculator belongs to stage 4.

Stage 4 · you are here

During an IVF cycle

Make sense of the numbers your clinic gives you.

Medicines
→
Egg collection
→
Your embryos

This calculator: Are my embryos growing on day 2 and 3?

Calculators for what comes next

How this is worked out

Exact calculationArithmetic on the numbers you enter. If your inputs are right, this figure is right.

Cleavage rate is the proportion of fertilised embryos still dividing normally by day 3. Most units expect above 85%, because meaningful attrition usually appears later, between day 3 and the blastocyst stage.

About this calculator

?What it tells you

Cleavage rate. How many fertilised embryos progressed through the cleavage stage by day 3.

✓When to use it

On day 3, when the embryology update comes through

iWhat you need

Cleaved embryos
Normally fertilised (2PN)

!What it cannot tell you

Cleavage rate is a weaker quality signal than blastocyst conversion.

Common questions

Is day 3 a good time to judge quality?

Only partly. Most embryos cleave; the informative attrition happens between day 3 and day 5. A good cleavage rate does not guarantee blastocysts.

Should we transfer on day 3?

If very few embryos are available, some units transfer earlier rather than risk none surviving to day 5. It is a genuine clinical judgement — ask what your unit would do and why.

My embryos cleaved but none reached blastocyst. Why?

Embryonic genome activation happens around day 3 — before that the embryo runs largely on maternal machinery. Arrest between day 3 and day 5 is where intrinsic embryo problems typically show, which is why the drop-off happens there and not earlier.

Sources

Most units expect the large majority of normally fertilised embryos to cleave. Meaningful attrition usually appears later, between day 3 and blastocyst.

In an emergency

If you have any of the warning signs listed here, don't wait for a test result or a calculator. Get help now.

112All emergencies, anywhere in India 108Ambulance

Also call your IVF clinic. Most clinics give an emergency number on your treatment or discharge sheet. Save it in your phone now, before you need it.